Glossary of Botanical Terms

Botanical Glossaries & Dictionaries

   Plant Identification Terminology by Harris and Harris.
This is a superb and indispensable glossary book with definitions and illustrations for several thousand botanical terms.

Illustrated Glossary of Compositae

Missouri Botanical Garden Botanical Research Glossary

Illustrated Glossary with Definitions

Flora of North America Glossary

Botanical Dictionary 

Pictured Interactive Biological Key

Dave's Garden Botanary

2017 Shenzhen International Code of Botanical Nomenclature Definition of Code Terms. The Code is revised every 6 years but because of COVID the meeting was not held in 2023.
It will be held in Madrid in July, 2024.

A Grammatical Dictionary of Botanical Latin

Dictionary of Botanical Epithets

Dictionary of Botanical Names 

Abaxial: Away from the axis. The abaxial side of a leaf; the back side of a leaf. See adaxial and dorsal.

Acaulescent: Stemless. See cauline.

aceae: Latin suffix meaning "family" or "group", as in Geraniaceae (the Geranium Family) and Liliaceae (the Lily Family). By international agreement, all scientific family names for plants end in "aceae". But there are several long-used family names which are also acceptable. See Plant Names.

Achene: A dry, indehiscent fruit formed from a superior ovary of one carpel and containing one seed which is free from the pericarp. However "achene" is commonly (and according to some authorities, incorrectly) used for dry one-seeded fruits in general, in particular, the one-seeded fruits of Asteraceae which are more properly called "cypselae", singular, "cypsela". See Illustrated Glossary of Compositae.

Actinomorphic: Having radial symmetry. Regular flowers, i.e., having all parts of the flower similar in size and arrangement on the receptacle so that if one were to cut the flower vertically in two anywhere, the two parts would be nearly identical appearing. See Hymenoxys hoopesii. Contrast with zygomorphic, irregular flowers.

Acuminate: Tapering to a sharp point from concave sides. "Acuminate" is one term used to describe the shape of a leaf tip. See "acute" immediately below. Acuminate, acute

Acute: Tapering to a point from straight sides, as in an upside down V. "Acute" is one term used to describe the shape of a leaf tip. See "acuminate" immediately above.

Adaxial: Toward the axis. The adaxial side of a leaf; the top side of a leaf. See abaxial and ventral.

Adnate: Attachment of unlike parts, e.g., fusion of stamens to the corolla. See connate.

Adventive: Not native to an area but introduced, established, reproducing, and spreading.

Albino Plants: Perhaps a half dozen times each year I come across white flowers on plants which normally have blue, purple, or red flowers. Often such white-flowering plants are called "albinos"; they are not. An albino plant would have white leaves, stems, etc; there would be no chlorophyll production and the plant would die not long after it flowered because it would run out of the energy given by chlorophyll.

Further, such white-flowering plants are not new, distinct species. They are the result of a small mutation and are otherwise identical to the blue, purple, and red-flowering plants.

The best term for such white flowering plants might be, "albiflora forms".

Click to read Greg Staple's very well-told tale about albiflora forms .

Below are photographs of a few albiflora forms. Click for more details about each species: Phacelia crenulata, Delphinium barbeyi, and Pedicularis groenlandica.

Click to see more albiflora forms on this website: Allium macropetalum, Polemonium confertum, Delphinium nuttallianum, Phacelia integrifolia, Veronica wormskjoldii, Hedysarum occidentale, Ipomopsis ramosa, Vesper bulbosus.

Phacelia crenulata      Delphinium barbeyi      Pedicularis groenlandica

Alpine: Above 11,500 feet (tree line).  Characterized by tundra: land of thin soil, rocks, a very short growing season, and frost any day of the year. Annually 30-55 inches of moisture, most from snow.  Magnificent carpets of dwarf flowering plants in July and August.

Alternate: See leaf position.

Ament: See catkin.

Angustifolia: Narrow leaves, as in Populus angustifolia.

Annual: A plant which completes its entire life cycle of root, stem, leaf, flower, and seed growth in just one year and then dies. See Biennial and Perennial.

Anthesis: Botanical term for "flowering time", e.g., "The plant has no basal leaves at anthesis". 

Anthus: Greek for "flower".

APG: Angiosperm Phylogeny Group. The "APG process trie[s] to produce a consensus classification that reflecte[s] results and opinions of experts in many groups of flowering plants". The APG continues to produce new information about the genetic relationship of plants. See APG IV here and here. The APG publishes periodically.

Apomixis/Apomictic:  Asexual reproduction.  Viable seed production without fertilization.  Taraxacum officinale (Dandelions) reproduce sexually or apomictically; Arnica cordifolia reproduces only apomictically.

Appressed: Pressed close or flat against another surface, as in hairs on a leaf or leaves appressed against a stem.

Areole: An organ (found only on Cactus) which gives rise to spines, flowers, stems, or roots.

Arvensis: Latin for "of the field", as in Cirsium arvense.

Ascending: Curved upward. Growing somewhat horizontally and then upward; obliquely upward and usually curved. See appressed and spreading.

Asteraceae: This is the largest plant family in the United States (~400 genera and ~2,400 species) and in the world (~1,900 genera and ~33,000 species). The term, "Compositae" (used in A Utah Flora) is an accepted, but now uncommonly used, alternate name for this family. The family has a number of common names: Sunflower, Aster, Daisy, and Composite Family. There are approximately 200 Asteraceae species on this website, i.e., about 20% of all species are Asteraceae. Worldwide the figure is approximately 19%.

See Illustrated Glossary of Compositae.

Similar Asteraceae are grouped into 12 subfamilies and about 43 tribes. In the United States there are 25 tribes with the largest being:

Astereae Tribe (Aster Tribe) with such related genera as Solidago, Grindelia, Chrysothamnus, Townsendia, and Erigeron;

Heliantheae Tribe (Sunflower Tribe) with such related genera as Encelia, Helianthus, Helianthella, Rudbeckia, and Wyethia;

Senecioneae Tribe (Groundsel Tribe) with such related genera as Tetradymia, Packera, Senecio, and Ligularia.

The Four Corners region has 10 tribes: Anthemideae, Astereae, Cardueae, Eupatorieae, Helinatheae, Inuleae, Lactuceae, Mutisieae, Senecioneae, and Vernonieae. See pages 14-15 of Intermountain Flora for a key to the tribes.

Asteraceae is made up of shrubs and herbs with inconspicuous to showy flower heads that appear to be one flower but are actually a composite of a number, often a very large number, of small flowers (best called "florets").

Flower heads of Asteraceae may be structured in one of the following ways:

1) Flower heads can contain only ray florets (also called "ligulate florets") with every corolla having one prominent, narrow, arching petal (called a "ray" or "ligule") which is actually a fusion of five petals (note the five lobes at the tip). Example: Taraxacum species (Dandelions).


2) Flower heads can contain only disk florets with tubular corollas having 5 small lobes but no elongated petal. Example: Carduus nutans (Musk Thistle).

Musk Thistle

3) Flower heads can contain disk florets packed together in the center of the flower head with ray florets surrounding them in a circle. The ray florets are very similar to ray/ligulate florets but each narrow, arching petal most often has three lobes, not five. Example: Hymenoxys hoopesii (Sneezeweed).


4) Flower heads can be similar to those in 3), but in addition to the three-lobed ray, there is a very short two-lobed ray on the opposite side of the corolla. Few Asteraceae species (none on this website and only a few in the Four Corners region) have this configuration.

Ligulate and ray florets may number from few to dozens. Disk florets are often in the many dozens.

Depending on the species, disk florets may be bisexual and fertile or may have only functional stamens. Rarely they are sterile.

Ray florets are usually pistillate, i.e., they lack stamens. They are sometimes sterile.

Ligulate florets have functional stamens and a fertile pistil.

An Asteraceae fruit is a "cypsela", a one-chambered, dry, hard fruit from an inferior ovary. Cypselae vary considerably in size depending on the Asteraceae species. Cypselae are often inaccurately referred to as "achenes".

For more details see Disk Flower.

Awn: A narrow bristle-like appendage. Asteraceae pappus hairs may be awn-shaped. See Bidens cernua and see the bottom of the Scorzonera page. See Illustrated Glossary of Compositae.

Banner: The topmost, relatively large, upright flower petal in many Fabaceae (Pea Family).  The "wings", which enclose the "keel", extend outward from the bottom of the banner. See Lupinus prunophilus and  Lathyrus pauciflorus.

Barbellate: Having minute prongs, as in the barbs on some Asteraceae pappus hairs. See Illustrated Glossary of Compositae.

Basal: At ground level. See "Leaf position".

Basifixed: Term used to describe the point of attachment of hairs. Attached only at their base, as in human hairs. Contrast with Malpighian.

Biennial: A plant which lives two years, producing a basal rosette of leaves the first year and a full plant, flower, and seed the second year followed by the death of the entire plant at the end of the second year. See Annual and Perennial.

Bisexual: Flowers having both stamens and pistils. Also called "perfect flowers".

Bracts: Modified leaves. Very small leaf-like growths. Some bracts encase the flower and then subtend the flower after the flower opens. All of the bracts that subtend a flower are together called the "involucre". The parts of the involucre may be given separate names: "bracts" for the outermost whorl, "calyx and sepals" within the bracts, and "petals" within the sepals.

In Asteraceae, the involucral flower head bracts are most often called "phyllaries" although a few floras call them "bracts". The individual Asteraceae florets within the flower head have no bracts/phyllaries. Instead they have pappas hairs, modified bracts, i.e. modified calyces.  See Arnica mollis.

Bristle: A fine, hair-like structure. Used to describe some types of pappus hairs. These pappus bristles may be capillary, awl, or plumose-shaped. See Illustrated Glossary of Compositae.

Bundled: See leaf position.

Caespitose: Low growing in tufts from a common point. A common term used as a specific epithet. Tufts are differentiated from "mat" and "pulvinate". "Mat" usually means "tightly spreading along the ground". "Pulvinus", "a swelling" leads to "pulvinate" "a small swollen-like mound". "Pulvinate" is most often used in the plant name, as in Physaria pulvinata.

Campanulate: Bell-shaped.

Calyx: The outer segment of the perianth that encloses and protects the petals and other floral parts when the flower is in bud, and then opens and clasps, spreads, and/or droops as the flower develops.  The individual parts of the calyx are called sepals. Sepals are often green and of various shapes and textures, but they can be as large (or even larger than) the petals in a flower and can be almost identical to the petals in shape, size, color, and texture. When they are so similar, they and the petals are termed "tepals".

Canescent: Coated so extensively with hairs as to have a gray/white cast. "Cana". "Incana".

Canyons: Deep and long depressions with walls of slopes and cliffs.  Pinyon Pine, Juniper, and Sagebrush are common on canyon walls in the Four Corners area, which is rich in deep, long, and beautiful red and white sandstone rock canyons.

Capillary: Long and thin hairs. In particular, used to describe thin, unbranched hairs (bristles) of many Asteraceae.

Capitate: Head-like.

Carpel: A flower's female reproductive organ, consisting of the stigma, style, and ovary and made of an inrolled leaf. The peapod is an example. Many flowers have more than one carpel and the carpels collectively are called the gynoecium. See pistillate, stamen, staminate.

Catkin: A type of inflorescence consisting of an often pendulous dense collection of unisexual flowers that have no petals. Also called an ament. See the whole page of Ostrya knowltonii. In all floras and in botanical dictionaries and botanical descriptions, the words "catkin"and "ament" are said to refer only to the dense collection of flowers, but the term is also used by everyone for "the dense collection of catkin seeds". I can find no one who knows what word should be used for catkin seeds.

Caudate: Tapering very quickly to a finely drawn out point as in the tip of Helianthus annuus phyllaries.

Caudex: The woody stem base of some herbaceous perennials. Although some floras indicate that caudices are below ground, others indicate they may be below or above ground. See Boechera.

Cauline:  On or pertaining to the stem, "cauline leaves".  "Acaulescent" means, therefore, "without a stem", as in plants which have leaves arising directly from the base of the plant at ground level. The plant has no stem. There are, however, almost always flower stems, "scapes". For acaulescent, see Micranthes.

Chaff: In Asteraceae (the Sunflower Family), a minute bract/scale-like, thin, dry plant structure sometimes present at the base of each floret (tiny flower). Chaff is attached to the receptacle. The presence, shape, and size of the chaff help you determine the genus of some Asteraceae. See Illustrated Glossary of Compositae.

Chartaceous: Papery, as in some sepals. See Symphyotrichum ericoides.

Ciliate: Fringed on the margins with hairs.  The presence or absence of these hairs is sometimes important in distinguishing among species.  Usually the cilia can best be seen with a 10x hand lens. See Monardella odoratissima and Asters.

Cladistics: A widely accepted phylogenetic method for classifying plants.  Cladistics makes assumptions about the primitiveness of a group of plants' characteristics and represents these in a branching diagram (a cladogram).  Other cladograms are drawn based on other assumptions about primitiveness of characteristics.  Through the process of: "if this, then this, but not that" and by working with probability theories, it is believed that cladistics will lead to an understanding of which characteristics are most primitive and which evolved.  It is believed that cladistics will produce a more accurate classification of plants.  Click to read more about cladistics: in the Utah Native Plant Society newsletter, on the Missouri Botanical Garden website, and in Wikipedia.

Claw: The very narrowed base of some broad flower petals or sepals. See Fendlera rupicola.

cm: centimeter

Colorado Plateau: See Four Corners.

Common Name: A name given to a plant by anyone in any language for any reason. See Plant Names for a discussion of why we should use scientific, not common names, how scientific names are arrived at, a brief history of the development of scientific names, why scientific names change, etc.  Very interesting.

Compound leaf: A leaf which is separated into two or more distinct leaflets. See Acer negundo. Also see leaf type.

Conifer: From the Latin "conus" (conical) and "ferre" (to bear), i.e., bearing a conical-shaped seed-bearing organ. However, not all conifers have conical-shaped reproductive organs. For instance, Junipers have a berry-like sphere.

In general, conifers are cone-bearing trees, as differentiated from flower-bearing trees. Conifers are gymnosperms; they have no flowers and bear naked seeds. Angiosperm trees have flowers and bear seeds encased in tissue, all together called the "fruit".

Conifer Leaf Drop: Almost all conifers have long, thin leaves (needles) similar to those of Pinus ponderosa, or scale-like leaves similar to those of Juniperus osteosperma. The lifespan of these leaves also differentiates conifers from angiosperm trees, for although angiosperm trees drop their leaves yearly, conifers retain their leaves a number of years. The retention of leaves leads us to call conifers "evergreens", but they are not really "ever green". Notice, for instance, that in the fall the older Pine trees in your area have yellowing leaves which eventually fall and cover the ground.

All mature conifers have a yearly leaf drop. However, only some leaves, the most mature, are dropped. Very few conifers, for instance, Larch and Bald Cypress drop all their leaves every year.

Most young conifers do not drop leaves until they reach 4-9 years of age, an age that varies with the species, latitude, and elevation. When they do begin dropping leaves, they drop the ones that grew in the very first year(s) of plant growth; they retain all other leaves and thus appear to be "ever green".

The number of years that conifers retain leaves varies with the conifer species, latitude, and elevation, but the range of leaf retention is generally from 3-7 years.

The United States Forest Service indicates that "High elevation white pines retain leaves for 5 to about 20 years, on average. Great Basin Bristlecone pine holds the record for the greatest leaf longevity - trees of that species can retain a leaf... for 40 years".

Purdue University Landscape Report indicates, "White pine and arborvitae needles live for 2-3 years, Austrian and Scots pine needles live for 3 years, red pine needles live for 4 years. Firs, Douglas fir, and hemlock needles last about 3-4 years. Spruce needles live 3-10 years depending on the species, with most lasting about 5 years".

The Arboricultural Research and Education Academy gives these figures for conifers leaf life spans:

Arborvitae (Thuja occidentalis) 2 to 4 years
Douglas-fir (Pseudotsuga menziesii) 5 to 7 years
Fir (Abies spp.) 3 to 5 or more years
Hemlock (Tsuga canadensis) 5 to 7
Juniper (Juniperus spp.) 3 to 7
Larch (Larix spp.) 0.5
Pine - Austrian (Pinus nigra) 3 to 4
Pine - bristlecone (Pinus aristata) 15 to 20
Pine - jack (Pinus banksiana) 2 to 4
Pine - Japanese red (Pinus densiflora) 3
Pine - Korean (Pinus koraiensis) 3
Pine - limber (Pinus flexilis) 5 to 6
Pine - mugo (Pinus mugo) 5 or more
Pine - ponderosa (Pinus ponderosa) 3
Pine - red (Pinus resinosa) 4
Pine - Scotch (Pinus sylvestris) 3
Pine - Swiss stone (Pinus cembra) 4 to 5
Pine - White (Pinus strobus) 2 to 3
Spruce (Picea spp.) 5 to 7
Yew (Taxus spp.) 3 to 7

Click to read detailed scholarly research that examined the relationship of latitude and temperature to leaf retention of five boreal forest species: Picea glauca, Picea mariana, Pinus banksiana, Pinus sylvestris, and Abies balsamea. As latitude increased and temperature decreased leaves were retained almost twice as many years, from about 5 to 9 years, 5 to 11 years, 3 to 6 years, 5 to 11 years, and 3 to 6 years for the five species mentioned above.

You can monitor leaf life span on conifers on your property by counting leaf scars on the branches and/or by tying a string behind new spring growth. Tape a label with the date onto the string -- or use flagging tape with the date written on it. See how many years those leaves last.

Connate: With similar parts united, e.g., petals fused into a tube. See adnate.

Convergent evolution: The development of similar features in different species as they adapt to similar environments.

Cordate: Heart-shaped.

Corolla: All of the petals of a flower taken together. Corolla shapes, sizes, colors, textures, etc. are highly variable and these qualities along with the various scents and nectars attract an enormous variety of bees, wasps, spiders, ants, birds, and people to plants.

Corymb: A type of spreading, racemose inflorescence (often flat-topped, sometimes rounded) in which each flower stem ("pedicel") originates from a different point on the main flower stem. Lower pedicels are longer than upper ones thus producing a flat-topped cluster. Umbels, another type of inflorescence, have pedicels which originate from the same point, as umbrella spokes do, so pedicels are of equal length. See Google Images  and  Heracleum maximum.

Crenate:  With rounded marginal teeth.

Cuneate: Wedge-shaped.

Cyme: An inflorescence in which flower stalks emerge from a single point (as do those in an umbel). Pedicels of a single flower alternate with peduncles of several flowers. Terminal flowers bloom first.  In "racemes" the first blooming flowers are at the bottom of the flower stalk. Click for cyme drawings.

Cypsela (plural "cypselae): A dry, indehiscent, one-seeded fruit formed from an inferior ovary. An Asteraceae fruit is most properly called a "cypsela", not an "achene". Unfortunately, "achene" is commonly used in place of "cypsela" for all dry one-seeded fruits. "Achene" most accurately refers to the fruit of a superior ovary. See Illustrated Glossary of Compositae.

Deciduous: Shedding leaves annually. Used to describe a plant (usually a tree) which sheds all of its leaves each year, usually in the fall.

Decumbent: Reclining on the ground but with ascending tips.

d: Abbreviation for decimeter, which equals 10 centimeters, which equals about 4 inches.

Decurrent: Leaf bases which grow down the stem and wrap at least partially around. Cirsium parryi.

Deflexed: Bent abruptly downward, as in the shape of some leaf tips.

Dehiscent: Splitting open at maturity.

Dentate: Toothed along the margin with the teeth pointing outward.

Depauperate: Significantly reduced from normal size or function.

Descriptions, botanical: A new plant's name and characteristics must be formally published for the plant's identity to be accepted by science. This description must also be accompanied by a specimen of the plant deposited in a herbarium for others to view. 

The formal, detailed write-up of a plant's characteristics follows an accepted pattern of analysis and descriptive format. The plant's presently accepted name and the botanist who named it come first followed by the name of the person describing the plant (if different from the person naming the plant). These are followed by past names ("synonyms"); perhaps a common name; a generalized overview of the plant including whether it is perennial, annual, etc.; then the details of the plant's morphology starting with the roots, stems, and leaves, then the flower in considerable detail, then the fruit, chromosomes, and finally notes on habitat, similar species, other botanist's agreements/disagreements with the descriptive notes, etc. 

Similar species are referred to and the plants position in a botanical key may be included.  Details about the plants location, range, unusual characteristics, etc. are included. An abstract both in the native language and Latin are included. (As of 2012, a Latin description is no longer a requirement.) 

A plant may inadvertently be described more than once by different botanists. Each description may result in a different scientific name until someone examines all the specimens and determines which are the same species and which name takes precedence, the latter according to the "International Code of Botanical Nomenclature". See Scientific Names and Plant Names and click to read the description of a plant Betty and I discovered.

Determinate: Describing an inflorescence in which the terminal bud opens first thus halting any further elongation of the main flowering axis. Contrast with indeterminate.

Dioecious: (Pronounced, die e shus) A dioecious species bears its male (staminate) flowers on one plant and female (pistillate) flowers on another. The Greek "dioecious" means "two houses".  See monoecious. Both dioecious and monoecious flowers are unisexual, i.e., imperfect. The terms "imperfect" and "perfect" have nothing to do with the quality or value or beauty of a flower. They are not judgmental terms.

Disjunct: Occurring in widely separated areas, as in disjunct populations of the same species. A disjunct population refers to species occurring far from their main population. See Triteleia grandiflora.

Disk flowers (or disc flowers) and ray flowers: What we perceive as a single flower in Asteraceae (the Sunflower Family) is actually a flower head composed of a number of tiny flowers packed into a disk (therefore "disk flowers"), or packed into a disk which is surrounded by equally tiny flowers that have an elongated appendage (called a petal or ligule or ray) (therefore "ray flowers"), or the flower head may have no disk flowers but just ray flowers.

See Illustrated Glossary of Compositae.

Many professional floras refer to each tiny Asteraceae flower in the head of flowers as a "floret", Latin for "small flower".

The Flora of North America indicates that in Asteraceae flower heads having all florets with a long, arching petal this petal is to be called a "ligule" and the floret is a "ligulate floret". The ligule is made up of 5 fused petals and there are 5 lobes terminating the ligule.

The FNA indicates that in Asteraceae flower heads having both disc and ray flowers, the flat portion is called a "lamina". The lamina is made up of 3 fused petals which typically terminate in 3 lobes. 

The Jepson Manual agrees with the FNA on the use of the word "ligule" for those Asteraceae having only ray flowers, but it uses the word "ray" not "lamina" for the ray flowers in an Asteraceae flowerhead made up of disk and ray florets.

Intermountain Flora uses "ray" and "ligule" interchangeably. Intermountain Flora gives very nice details about Asteraceae, its tribes, genera, and species in volume 5, Asterales.

Flora of Colorado indicates that Asteraceae has disk flowers, ray flowers, or "ligulate ray" flowers.

A review of other professional floras shows that they choose only one of the above words, i.e., "ray", "ligule", or "lamina", for the Asteraceae flower petals or they make no mention of any of the words. Some floras mistakenly call the elongated appendage "a ray flower" or a "ray floret". These two terms are obviously incorrect as "floret" refers to the entire flower, not to one part.

In this website I refer to the Asteraceae petal as a "ray" or as a "petal".

It is rare to find floras which indicate that the petal-like appendage of a ray flower is indeed a "petal", but it is a petal. It is the flattened corolla extension formed by a fusion of (usually) three or five petals.

Here are a few details to add to the above:

1) Disk flowers ("disk florets") are numerous and packed tightly. Each disk flower is made up of fused petals and is very small, thin, vertical, and tubular, almost always with 5 tiny lobes. In the drawing below from Wikipedia #1 is the two parted stigma, 2 is the style, 3 shows the fusion of 5 anthers which surround the style, 4 points to the lobes of the five petals which are fused to form the tubular corolla, 5 is the reduced calyx which will become the pappus, and 6 is the ovary, the developing seed.

                                                                        Disk flower

2) Ray flowers ("ray florets") are typically few (but may be in the dozens depending on the species), and they surround the disk flowers in one circle. Ray flowers may be more numerous when there are no disk flowers. Ray flowers are very small, thin, vertical, and tubular, with one elongated (quite short to long), strap-like corolla extension, called the "lamina" or the "ray" or the "ligule", i.e., it is the "petal". In the drawing below from Wikipedia #1 is the ray, 2 is the style, 3 is the two-parted stigma, 4 is the reduced calyx which will become the pappus, and 5 is the ovary, the developing seed.

                                                                                        Ray flower

Some Asteraceae species are composed only of disk flowers (Thistles, for instance): Carduus nutans.
Some Asteraceae are composed only of ray flowers (Dandelions, for instance): Taraxacum officinale.
any Asteraceae are composed of both disk and ray flowers (the large annual sunflowers along roadsides, for instance): Helianthus annuus.

Asteraceae disk flowers are usually bisexual and fertile, each producing one seed, but some Asteraceae species have disk flowers that only have stamens and therefore do not produce seed.

Most species of Asteraceae ray flowers are often pistillate, i.e., they have only pistils and, if fertile, produce one seed, but in some Asteraceae species, ray flowers may be bisexual, sterile, or contain no sexual parts.

See Arnica mollis   Oxytenia acerosa 

Also see above, Asteraceae

Ohio plants, Asteraceae

Distal: Toward the tip, opposite the point of attachment. See proximal.

Disjunct population: A population of a species native to an area but also found far from that main area. For instance, Penstemon venustus is a native North American species found almost exclusively in the area where Idaho, Oregon, and Washington meet, but there is a small disjunct population in Utah and another near Silverton, Colorado, even farther from the main population.

Disturbed Areas: Roadsides, mined areas, grazed lands, timbered lands, and ski slopes are unnatural disturbed areas.  There are also natural disturbed areas: snow and rock avalanche areas; ground burrowings from gophers, prairie dogs, etc.; Elk wallows, animal tracks, and animal foraging.

Divaricate: Extremely divergent.

Divergent: Spreading away from the main axis of growth.

Dolabriform Hairs: See Malpighian Hairs.

Dorsal: The back or outward surface, as in the lower surface of a leaf. Also abaxial. See ventral.

Drought:  Precipitation in the Four Corners area averages from 6 to 15 inches per year in the elevations of 5,000 to 7,000 feet and increases dramatically up to the high montane areas that receive 200-400 inches of snow per year and another 20 inches of rain. 

But precipitation is highly erratic; few months or years are average and, in fact, some months or even years are considerably wetter or drier than average.  The "average" precipitation is, therefore, not the "usual" precipitation.

Plants of the Southwest are comfortable with these variations; they have evolved in and continue to thrive in these erratic conditions.  Human beings are not comfortable with varying precipitation levels; they want a consistent water supply for boating, watering lawns, and golfing.

Drought is made harsher for human beings by three factors: hard freezes in June, high winds, and above normal temperatures which evaporate snow from the mountains and water from reservoirs.  Less snow means less water in the rivers, which means less water in the river-fed reservoirs. There will then be less irrigation water, fewer crops to feed the cattle, less cattle money for purchases at local businesses, less tax money collected and thus less money for road repairs, schools, health care, golf courses. 

We have tried to build a watered way of life for too many people in the erratically dry Southwest.

Wild animals, too, can be caught in a negative chain of events: a freeze in June means that many Oaks will have their leaves and flowers frozen.  The acorn crop, which many wild creatures depend on, will be sharply reduced. Oaks put out a second set of leaves so they continue to thrive, but they do not put on a second growth of acorns. Those creatures which eat acorns have to make do with other wild foods. 

What are the results of drought for wildflowers?  The number and size of plants and flowers will be greatly reduced. Flowers, and sometimes even plants, will be confined to little rivulets of water across meadows, in seeps, etc.  Low desert areas may have very few flowers.  Plants will bloom weeks early or late. There will be no flowers for some species and few flowers for most species. Flowers will last a short time. Those plants that do flower will produce seeds that have a better chance of surviving dry conditions.  Evolution continues.

E: Without, as in ebractate, eglandular.

Elevation: The vertical distance above mean sea level of an object which is on the surface of the earth. ("Altitude" refers to the vertical distance above mean sea level (or another reference point) of an object which is above the surface of the earth.) So "elevation" is the appropriate term when discussing the location of flowers, people walking, towns, and roads, all of which are on the surface of the earth. "Altitude" is the appropriate term when discussing the location of an airplane, skydiver, or migrating bird, all of which are above the surface of the earth.

Endemic: Found only in a small region, in a particular ecological niche. "Ipomopsis ramosa is endemic to Dolores County, Colorado."

Entire: Not toothed, notched, lobed, or divided. Especially pertaining to leaves. See leaf blade margin.

Epigynous: With floral parts attached to the top of the ovary. An inferior ovary.

Erect: Relatively straight upward growth. See "decumbent" and "ascending".

Erose: With margins irregularly toothed, seemingly gnawed.

Evergreen: A plant which retains a large portion of its green leaves all year. Evergreen plants do drop leaves at various yearly intervals. Often all leaves are retained for the first 3-8 years of growth on the new stems. Then the oldest growth of leaves yellow and drop.

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Falcate: Sickle-shaped. Shaped like the beak of a falcon.

Family: A large grouping of plants with shared characteristics.  Often these characteristics are visually apparent to the unaided eye: the green, slender, long and narrow-leaved upright structure of grasses; the wide, flattened disc usually fringed by numerous, long, thin petals flared outwards of the Sunflowers; the cross-shaped four-petaled flowers of the Mustards; the umbrella-like flower structure of the Parsleys; the long thin needle leaves of Conifers.

Learning such key characteristics of just 19 families will, as William Weber points out in his Colorado Flora: Western Slope, assist in identifying over 75% of the plants in the Four Corners region (and in most other areas). The Western slope of the Colorado Rockies has over 2,100 species in 139 families; Weber indicates that almost 1600 species are in 19 families. 

Knowing characteristics of just six families will open the door to almost half the plants. The top six families are: Asteraceae (Sunflower) with 354 species, Poaceae (Grasses) 208, Fabaceae (Pea) 138, Cyperaceae (Sedges) 123, Brassicaceae (Mustards) 119, and Scrophulariaceae (the old Snapdragon Family) 99. 

See Genus, Species, Scientific Name, and Plant Names. Scientific names shown in bold on the enlarged photo pages are the currently accepted names according to John Kartesz's Synthesis of the North American Flora and BONAP.  Scientific names shown in normal font are synonyms.

Farinose: Covered with a mealy, powdery substance.

Fascicle: A bundle or cluster as in "a fascicle of stems" or "the flowers are in a fascicle". See Orobanche fasciculata.

Fell-field: A wind-scoured, thin-soiled, few-flowered rocky flat at alpine and arctic elevations. Fell-fields are littered with various size rocks and boulders, flattened or piled.

Floret: Latin, meaning "a small flower". Often used in referring to the small flowers that make up an Asteraceae flower head.

Flower: The reproductive portion of some plants, consisting of either pistils or stamens (imperfect flowers) or both (perfect flowers) and usually including sepals and petals. 

Because a plant has flowers it does not necessarily follow that the plant reproduces itself exclusively by the ripened ovary of this flower.  Some plants propagate more from underground root spread (Vaccinium myrtillus) or from above ground stolons (Fragaria) or from plant parts that fall to the ground or are carried to new ground by animals and then root (Opuntia).  And plants such as ferns do not flower at all, but they instead have spores, reproductive cells that can give rise to a new plant.

Some plants have a very short flowering period, others bloom the entire summer.  Some plants put out a single flower, others have numerous flowers, either over a long period of time or within a few days.  Some individual flowers last part of a day; others for many days.  Some flowers open early in the day, some in the heat of the day, others at night. Some flowers open and close a number of times over a number of days; some flowers remain open until they wither. 

Flowering Month: The dates for flowering often vary as much as several weeks from year to year, for flowering time is dependent on temperature, moisture, wind, etc. -- all of which are especially variable in desert and mountain areas. Also note that some spring and summer flowering species, especially those at lower elevations, can have a second flowering in the fall, especially when fall temperatures are mild and ground moisture is adequate. Dates for fall flowering of these species may not be listed in the "Select Plant Characteristics" key because such flowerings are erratic.

Follicle: A dry, dehiscent fruit, composed of a single carpel that opens along one side. See the red arrows at Delphinium nuttallianum.

Foothills: From 6,500 to 8,000 feet in the Four Corners area, but lower along the Front Range. Composed of Pinyon Pine, Juniper, and Oak forests, often quite thick. Pockets of Douglas Firs.  Ponderosa Pine at higher elevations.  Numerous shrubs: Serviceberry, Mountain Mahogany, Snowberry. Annually about 14-25 inches of moisture, about half from snow. Moderate wildflower growth in May and June.

Forb: Herbaceous plants other than grasses.

Four Corners:  The area covered in this website extends in a hundred and fifty mile radius from the Four Corners, the meeting point of the borders of Colorado, New Mexico, Arizona, and Utah.  The area covered is bounded on the east by the Continental Divide at Wolf Creek Pass just east of Pagosa Springs, Colorado; on the southeast by the Ojito Wilderness Area north of Albuquerque, New Mexico; on the southwest by Petrified Forest National Park, Arizona; on the northwest by Grand Staircase/Escalante National Monument, Utah; and on the north by Arches and Black Canyon of the Gunnison National Parks.  The Four Corners area is part of the larger Colorado Plateau: the mountains, mesas, canyons, and semi-desert lands which are drained by the middle section of the Colorado River.

Fruit: A ripened ovary.

Fusiform: Spindle-shaped, i.e., broadest in the middle and tapering at both ends. See Mertensia fusiformis.

Galea: Hood-like upper lip of some two-lipped corollas. See Pedicularis.

Gall:  An abnormal bulbous formation on plant leaves or stems.  Galls result from a plant's attempt to protect itself from an unusual occurrence, usually a mass of insect eggs deposited on its surface.  Plant cells multiply rapidly to isolate the foreign substance, but this at the same time provides shelter for the substance.  The plant suffers little damage from the insects or the gall.  Picture of gall.

Genus: A subdivision of the Family in which all members have a significant number of similar (or identical) characteristics.  With practice an amateur can often determine the genus without recourse to detailed botanical texts and a magnifying glass. 

The genus name is capitalized and accompanied by and followed by the specific name in lower case; both are italicized, for example, Rosa woodsiiRosa is the genus and woodsii is the specific name (also called the specific epithet).

Scientific names shown in bold on the enlarged photo pages of this website are the currently accepted names according to John Kartesz's Synthesis of the North American Flora and Kartesz's online BONAP.  Scientific names shown in normal font are synonyms. See Family, Species, Scientific name, and especially Plant Names.

Glabrous: Smooth, without hairs. Whether a twig, stem, or leaf is glabrous or pubescent often is important in distinguishing between species, but the amount of hairiness often varies with the age of the plant. See pubescent.

Gland: A protuberance, often a hair-like structure, that secretes sticky or oily substances which often impart a stickiness and an odor (often pleasant) to the plant.

Glandular: Having glands, sticky. "Glandular" is often used to describe plant hairs which are ball-tipped with glandularity imparting a stickiness to the plant which is observable because dirt sticks to the plant, because the plant feels sticky, and because there is often a smell (often pleasant) associated with the glandularity. Ipomopsis ramosa  Penstemon breviculus.

Glaucous: With a whitish, often waxy, coating. Pruinose. Streptanthus cordatus.

Glochids: Tiny barbed hairs which grow from areoles of cacti. Opuntia phaeacantha.

Glomerate (glomerules): Crowded into a compact, spherical mass. Ball-like. Cymopterus glomeratus. Chenopodium.

Gracilis: Slender.

Grandiflora: Large-flowered. Such terms as "grandiflora", "grandifolia", "parviflora" ("small-flowered), "angustifolia" ("narrow-leaved"), "latifolia" ("wide-leaved") are, of course, relative terms. Such terms usually indicate that this flower or leaf is large relative to other flowers or leaves on other species in this genus. So even though to our eyes a "grand flower" may seem pretty small, it may actually be pretty big compared to other flowers in its genus.

If you are trying to compare flower or leaf sizes within a genus, your task can be made more difficult when the genus name has been changed, as for instance, "Hymenoxys grandiflora".  The species was first named "Actinella grandiflora" and that genus was broken into "Hymenoxys" and "Tetraneuris".

Gynoecium: Collective name for all the carpels in a single flower.

Gynophore: A stalk which supports the entire pistil. A gynophore is found on some species. It originates from the flower receptacle.

Habit: The general appearance, characteristic form, or mode of growth of a plant.

Habitat: As used in this website, "habitat" refers to the environmental components (rocks, wetlands, woodlands, etc.) in which a plant best survives.

Hemi-parasite: Partially parasitic. Describing a plant which can produce part (sometimes all) of its needs through photosynthesis but may obtain nutrients from the roots of other plants. Examples: Castilleja and Pedicularis.

Herb or herbaceous: A plant whose stems die back to the ground in the winter. See Woody.

Hirsute: With stiff, coarse hairs.

Hypanthium: The swollen cup-like structure formed by the fused bases of the stamens, petals, and sepals. See Lithophragma tenellum.

Hypogynous: With floral parts attached below the ovary. A superior ovary. Arnica mollis.

Imbricate: Shingled, overlapping as in many Asteraceae phyllaries. See Xanthisma grindelioides.

Imperfect flowers: Unisexual. Flowers with only stamens or only pistils, never both. Contrast with perfect and bisexual. The terms "imperfect" and "perfect" have nothing to do with the quality or value or beauty of a flower. They are not judgmental terms.

Incana: Coated so extensively with hairs as to have a gray/white cast. Also, canescent.

Indeterminate: Describing an inflorescence in which the lower buds open first thus allowing continued elongation of the main flowering axis. Contrast with determinate.

Inferior: Epigynous. Attached below. Commonly used to describe the position of a flower's ovary in relation to the point of attachment of the petals and sepals. An inferior ovary is below the point of attachment of the sepals and petals. Contrast with superior. The term has nothing to do with the quality of the ovary; the term does not mean "of less value". See Epilobium.

Inflorescence: A flower cluster. The main types of inflorescences are spikes, racemes, panicles, corymbs, umbels, and cymes.

Introgression: Movement of genes between species.

Involucre, involucel: The cluster of bracts that subtends a flower. See, for instance, Lonicera involucrata. An involucel is smaller than the involucre of that same plant. See Vesper. Asteraceae bracts are usually called "phyllaries".

Involute: With margins rolled upward and inward onto the upper side of a leaf. See revolute.

Irregular Flowers: Zygomorphic. Asymmetrical flowers. Such flowers can be divided only one way to produce mirror images. The parts of the flower are dissimilar in size or shape and are not arranged symmetrically on the receptacle so that if one were to make a vertical cut dividing the flower, the two halves would not, except in only one place, one cut, look alikeCalypso bulbosa. Contrast with regular flower, actinomorphic.

Keying a Plant: The process of identifying a plant with a botanical text. Most professional, detailed, accurate keys are "dichotomous", i.e., you are presented with two either/or questions about plants. You select one and that moves you on to another two questions. Eventually you have only one choice: the plant you are trying to identify. Simple sounding. Difficult, time-consuming, and rewarding in practice. See Scorzonera laciniata for an example of the difficulties in keying. Click to learn about how to use a botanical key.

Laciniate: Cut into into narrow, irregular lobes or segments. Scorzonera laciniata.

Laevigate: Lustrous, shiny.

Lamina: The expanded portion of a leaf or petal, as in the elongated ray petal of an Asteraceae ray flower.

Lanate: Woolly. Used in describing the hairs on a plant. See the similar terms, villous and tomentose.

Latiflora: Wide flowers.

Latifolia: Wide leaves.

Latin name: See Scientific name.

Leaf blade margin: Leaves can be entire, i.e., have smooth edges that are not at all toothed, lobed, or divided, or they can be compound with irregular margins that might be toothed, serrated, lobed gently, cut shallowly or deeply, etc.

The leaf margin is one of several leaf characteristics helpful in identifying a species. Click to see leaf blade margin photographs.

Leaf blade shape: From species to species, leaf shape varies enormously in length, width, and proportions, and there are numerous terms to describe these various leaf shapes: lanceolate, oblanceolate, ovoid, obovoid, linear, spatulate, oblong, cordate, orbicular, etc. A number of species have leaves of varying shapes.

The shape of a leaf blade is one of several leaf characteristics helpful in identifying a species. Click to see leaf blade shape photographs.

Leaf position: Leaves can grow from opposite sides of a stem; or leaves can grow on one side of a stem and then on the other side at a higher level, i.e., alternate; or leaves can grow in tufts at the base of the stem; or leaves can grow in whorls around a single area on the stem; or leaves can spiral around a stem; or leaves can grow in bundles from the same point on a stem.

A species can have leaves growing in several of the above positions, e.g., many plants have basal leaves and they also have leaves on the stem. Some plants have no stem leaves. Some have no basal leaves. Some plants have both opposite and alternate leaves.

Many plants have leaves in certain positions, say basal, early in the season, but these leaves wither and disappear as the plant ages. Keys for identifying species almost always give characteristics at full maturity of the flowers, and one identifying characteristic you might be asked about in a key is whether and where there are leaves at flowering time (anthesis).

The leaf position is one of several leaf characteristics helpful in identifying a species. Click to see leaf position photographs.

Leaf type: Leaves are either simple, i.e., the leaf blade is not divided into separate leaflets., or leaves are compound, i.e., the leaf blade is divided into separate leaflets. Simple leaves might have smooth margins, toothed margins, lobed margins, etc., but the indentations in the leaf never reach all the way to the center vein (the rachis). Compound leaves might have leaflets with smooth margins, toothed margins, lobed margins, etc. The small leaflets might be cut again to their rachis thus producing smaller and smaller leaflets.

The leaf type is one of several leaf characteristics helpful in identifying a species. Click to see leaf type photographs. Click for more leaf type photographs.

Lentiginous: Scurfy, covered with small scales.

Leucanthus: White-flowered.

Ligule: A strap-shaped organ. In Asteraceae, the flattened part of a ray floret. Also called the "ray". This organ is usually made up of 3 or 5 fused petals appearing as one and having 3 or 5 lobes. "Ligule" sometimes is used for the ray of just those Asteraceae having only ray flowers (with 5 lobes) in the flower head (Dandelions, for instance). Also see "ray".

Limb: The expanded end of a tubular or otherwise fused corolla (as mentioned immediately above). Measurements given for a limb are for the entire width of the top of the flower, i.e., from the tip of the lobes on one side to the tip of the lobes on the other side of the expanded portion. See throat and tube.

Lobe: An extending, usually rounded, division of an organ, such as, the wavy, indented edges of some oak leaves and the tips of many tubular flowers. See Penstemons. See sinus.

Locules: Cells or chambers, as in the cells of an ovary.

Lutea: Yellow.

Malpighian Hairs: Hairs which lie very close to and parallel to (almost flat against) the plant surface but are not attached to the surface at either end of the hair.  Instead they are attached somewhere along the length of the hair (often toward the middle) by a very minute projection of the hair.  Both ends of the hair taper to a point and the hair is thus a squat T-shape, similar to a pick-axe head. Also called "dolabriform hairs". See Astragalus ceramicus. Contrast with basifixed.

m: meter

Marcescent: Withered but persistent, as in some basal leaves.

Meadows: Large grass and wildflower-filled areas with few, if any, trees.

mm: millimeter

Monocarpic: A monocarpic plant is one which grows for a number of years until it flowers for the first and only time, fruits, and dies.  The Century Plant is monocarpic.  See Frasera speciosa and Eriogonum alatum for examples of two fascinating monocarpic plants in the Four Corners. 

Monoecious: (Pronounced, mow knee shus) A monoecious species bears male (staminate) flowers and female (pistillate) flowers on the same plant and thus all plants can bear fruit. The Greek "monoecious" means "one house". See dioecious. Both dioecious and monoecious flowers are unisexual, i.e., imperfect. The terms "imperfect" and "perfect" have nothing to do with the quality or value or beauty of a flower. They are not judgmental terms.

Montane: In the Four Corners area, 8,000 to 10,000 feet.  Open Aspen forests, sometimes with heavy undergrowth of shrubs (Snowberry, Currants, Elderberry). Colorado Blue Spruce in moist areas.  At lower elevations some large stands of Ponderosa Pine with scattered Douglas Fir on north facing slopes. Annually about 18-30 inches of moisture 1/2 to 3/4 from snow. Moderate to lush wildflower growth from June-August.

Mucronate: Tipped with a short, sharp, abrupt point as in some leaves.

Native species: A term used for species that we know have existed in an area as far back as records have been kept. As used in this website, "native species" means that the species has been present in the Four Corners region for at least all of historic times.

Nerves: Used most often to refer to the veins of leaves. Helianthella quinquenervis.

Node: The point at which there is an attached growth, as in the place where each leaf is attached.

Noxious Weed: Often this term is used in a very specific legal manner to describe a plant which has been introduced to a location, is a non-native plant, and which often crowds out native species or species of economic value.  See the full page discussion of the noxious weed problem.

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Ob: Inverted. An oblanceolate leaf has the inverted shape of a lanceolate leaf, i.e., it has its narrowest part at the point of attachment and then the leaf gradually widens.

Ochroleucous: Yellow-white.

Ocrea: A sheath of united stipules around the stems of many Polygonaceae species.

Officinale: A Latin term meaning "a shop" or "carried in a shop". Botanically, "officinale" came to mean, "a plant carried in an office, i.e., an apothecary shop".  Taraxacum officinale, Cynoglossum officinale

Oides: Similar to, as in Populus deltoides, similar to the shape of a delta. Chaetopappa ericoides, similar to Ericaceae, heathers. Most often pronounced, "oi des", but more appropriately should be pronounced, "o e das".

Openings: Small rock or meadow clearings in woods.

Opposite: See leaf position.

Panicle: A type of inflorescence in which branched flower stalks are attached to the main flower stem, i.e., a panicle is a branched raceme. The bottom flowers in a panicle open first. See thyrse.

Pappus (plural "pappi"): In many Asteraceae species pappi are the greatly modified calyces which grow from the apex of the seed (the "cypsela"). They are variously shaped and sized scales, bristles, or awns, all frequently silvery white. Pappi are often all referred to as "pappus hairs". The texture, number, and shape of the pappi are key elements in distinguishing between genera and species in Asteraceae. See Heterotheca zionensis for a close-up of inner and outer pappus hairs. Also see Arnica mollis.

It should be noted that almost all floras use the words scale, bristle, or awn to describe the shape of pappi, but in fact if we were to look at all pappi we would see a gradual gradation from scale to bristle to awn.

The pappus serves to protect the cypsela from predation and to assist in dispersing the cypsela. 

See Illustrated Glossary of Compositae.

See Scorzonera laciniata for a discussion of the confusing definition given to pappus hairs and pappus scales by the Flora of North America.  

See the Arnica page for photos of pappus and also see Taraxacum officinale and Senecio spartioides for a view of pappus hairs that we all know.

Parasitic: A plant that lives off the live tissue of other plants and fungi. See saprophytic.

Parviflorum: Small-flowered.

Pauciflorus: Few-flowered.

Pedicel: The stem of a single flower. If a flower has no stem it is said to be "sessile".  See "peduncle" immediately below.

Peduncle: The common stalk of a cluster of flowers.  See "Pedicel".

Perfect flowers: Bisexual. Each flower has both stamens and pistils. Contrast with imperfect and unisexual. The terms "perfect" and "imperfect" have nothing to do with the quality or value or beauty of a flower. They are not judgmental terms.

Perennial: A plant that grows for many years. But it should be noted that there are plants that grow for many years but flower only once and then die. These are "monocarpic perennials" and are such common species as Frasera speciosa (Green Gentian), Ipomopsis aggregata (Scarlet Gilia), and Hymenoxys grandiflora (Old Man of the Mountain). See Annual and Biennial.

Perfoliate: Describing a leaf which completely surrounds the stem to which it is attached.

Perianth: The outer whorl of plant parts that surround the inner reproductive parts, i.e., the calyx (all the sepals) and corolla (all the petals) of a flower taken collectively.

Just a few botanical glossaries add "especially when the calyx and corolla are similar". These additional words are quite confusing. The same botanical glossaries that add the "especially when... similar" words also indicate that when the calyx and corolla are "similar", they are to be called "tepals", so if "perianth" applies "especially" when parts are similar, is there no term that "always" indicates the collection of the calyx and petals?

The vast majority of glossaries use the term "perianth" without any reference to the similarity of the calyx and corolla.

Perhaps the most sensible definition of perianth is that given by the Intermountain Flora, "all of the sepals and petals (or tepals) of a flower, collectively". So whether the calyx and corolla are quite different from each other in shape, color, size, and texture (as they are in most flowering plants) or whether the calyx and corolla are very similar and then called "tepals" (as they are in some species), we call the total collection, "perianth".

Pericarp: The fruit wall. The structure surrounding the seed(s). An obvious example would be the fleshy (and edible) portion of the apple. Much less obvious and difficult to see even with a hand lens or microscope would be the tiny fraction of a millimeter skin-like covering of the Chenopodium seed. The difficulty in seeing the Chenopodium pericarp (and seeing if it adheres to the seed) makes identifying Chenopodiums to the species level difficult since most keys rely on the pericarp adherence to the seed as a distinguishing characteristic. Click to see Chenopodiums.

Petal: One of the segments of the corolla, the innermost whorl of the perianth which surrounds the sexual parts of a flower. Petals are often showy and are one of the allures of flowers that attract pollinators. Some more ancient species of flowers have no petals and the sepals then are often showy. Petals and sepals are sometimes very similar in shape, size, color, and texture and then are termed "tepals", not sepals or petals.

Petiole: The stem of a leaf. "Petiolate" means, "with a petiole".

Phila: Loving.

Phyllaries: The modified leaves that cover and then subtend flower heads in Asteraceae. Also called "bracts". All of the phyllaries/bracts that subtend a flower are together called the "involucre". Photographs of phyllaries: Grindellia, Dieteria, Aster, Arnica mollis.

Phylogenetics: The system of plant classification that tries to reflect evolution. At the beginning of the 20th century phylogenetics arose from Darwin's thinking and it is still evolving as it searches for a basis for ordering plants in their evolutionary sequence. Early phylogenetic systems started with basic assumptions about which features of plants were most primitive and which were derived, evolved characteristics.  Present classification tries to base the ordering of plants on scientifically verifiable, rather than on subjective, assumptions about primitive versus evolved traits.  See cladistics.

Pilose: Bearing long, soft, straight hairs. This is one of many terms describing the shape and texture of plant hairs.

Pinna, Pinnate, pinnatifid, pinnatisect: The Latin "pinna" means "feathered". The term is used to describe leaves that have a primary central midrib from which leaf subdivisions branch, i.e., the leaf is cut into a number of subdivisions called leaflets or "pinna" (plural, "pinnae"). Each of these pinna might be cut again into divisions and these divisions can again be cut. Click to see. And click again.

There are various terms to describe how deep the cut is in the leaf or leaflet and whether the individual segments have a stem. Most botanists agree with the following:

If the leaf is cut about half way to the midrib (but not to the midrib), the leaf is said to be "pinnatifid".

If the leaf is cut to the midrib, it is said to be "pinnatisect".

Many plants have pinnate leaves: Ferns, Mimosas, Ashes, Peas.

Pistillate: Containing only carpels, only female floral parts. See staminate, carpellate.

Plumose: Feathery, i.e., having hairs or fine bristle on both sides of the main axis. Often used in describing the shape of pappus hairs. Arnica mollis.

See Illustrated Glossary of Compositae.

Proximal: At the base. The lower end near the point of attachment. See distal.

Pruinose: Glaucous. With a white waxy or dusty coating.

Puberulent: Minutely pubescent with fine, short hairs.

Pubescent: Hairy. Pubescence is a distinguishing factor in plant identification.  Pubescence may vary from leaf to twig to stem and with the age of the plant. Pubescent sometimes means, "with short, soft hairs". See glabrous.

Pulvinate: Cushion-like or mat-like growth habit. Physaria pulvinata.

Pumila: Dwarf, small.

Pustulose: With small blisters (pustules) at the base of a hair.

Raceme: An elongated type of inflorescence with individual flowers attached to a central stalk by a flower stem (a pedicel).  See Actaea rubra for an example of a raceme. A raceme flower arrangement also can refer to the general habit of flowers blooming first at the bottom of the stalk.  Racemes, spikes, umbels, and corymbs flower from the bottom up.  Cyme flower arrangements bloom first at the top of the stalk.

Rachis: A main axis, such as that of a compound leaf.  The stem to which each leaflet is attached.  Click to see the red rachis of Asplenium trichomanes.

Ramos: Branched. Ipomopsis ramosa.

Rare: The term "rare" is used by most lay people to mean "unusual" or "not seen very often", but it has a more precise scientific meaning. The New Mexico Rare Plant Technical Council defines it as follows:

A taxon that is narrowly endemic to a specific geographic feature (e.g., mountain range; geologic outcrop) or subset area of a phytogeographic region (e.g., southern Rocky Mountains, northern Chihuahuan desert). It can be locally abundant within its narrow range, but typically will not extend more than 100 miles in length of range; OR A taxon that is more widespread, but is numerically rare - never locally common - throughout its range or is numerically abundant only in a few small, widely scattered habitats.

See the Colorado Rare Plant Guide for further information.

Ray: The elongated flattened part of the Asteraceae (Sunflower Family) ray flower, the corolla. The lamina. The ray is usually made up of 3 or 5 fused petals. See "ligule". Also, the stem of an umbel.

Ray Flowers: One type of small flower (a "floret") in the flower head of some Asteraceae. Ray flowers have an elongated, flattened appendage (most often yellow and relatively long, made up of 3 or 5 fused petals) and called by various floras a ligule or a lamina or a ray. See Disk Flowers.

Also see above, Asteraceae.

Receptacle: The uppermost portion of the flower pedicel or peduncle to which the floral parts are attached. Especially in keying Asteraceae, one is sometimes asked about the structure of the receptacle. See the second from the top photograph at Brickellia oblongifolia. Also see "chaff".

See Illustrated Glossary of Compositae.

Regular Flowers: Actinomorphic. Symmetrical flowers. All parts of the flower are similar in size and arrangement on the receptacle so that if one were to cut the flower vertically in two anywhere, the two parts would be nearly identical appearing. See Hymenoxys hoopesii. Contrast with irregular flowers. 

Recurved: Curved backward. See the last photograph at Grindelia squarrosa.

Reniform: Kidney-shaped.

Reticulate: A network of veins. Net-veined. Salix nivalis.

Retrorse: Directed backward or downward. Revolute. Eriogonum leptophyllum.

Revolute: Retrorse. With margins rolled backward and under onto the lower side of a leaf. Often used to describe the edge of a leaf. See involute.

Rhizomatous:  Referring to a fairly common method of reproduction in which new plants arise from nodes on rhizomes, horizontal underground stems. Roots do not have nodes and are not the same as rhizomes. Species that are rhizomatous spread in tight colonies of many plants. Thermopsis montanus, Erigeron ursinus, Sidalcea candida, Symphyotrichum lanceolatum.

Rocks: Areas of large rock in canyons or mountains.

Rosette: Usually used to describe a dense cluster of leaves at the base of a plant, a basal rosette. Eriogonum alatum.

Rostrum: A beak-like structure.

Ruderal: Growing in disturbed habitats. Weedy.

Runcinate: Saw-toothed or sharply incised with retrose teeth, i.e., with teeth pointing backward or downward.


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Samara: A winged seed such as found in Box Elders, various other Maples, Elms, etc.

Saprophytic: An obsolete term that meant, "a plant that lives off dead organic material".  Research has shown that no plants live off dead organic material; only fungi do that.  It is now known that plants described as saprophytes are actually parasites living off fungi.  The mycorrhizal fungi transfer nutrients from the host plant to the parasite. The fungi have a mutualistic relation with various host plants.

Plants formerly considered saprophytes are now considered parasites and they are called "myco-heterophytes" or "myco-heterotrophs". See parasitic.

Scabrous: Rough to the touch due to the plant's upper cell structure and/or to the presence of short, stiff hairs.

Scale: Small, dry, or vestigial organ. Describing one form of pappus hairs which are flattened. See the bottom of the page at Scorzonera.

Scape: A leafless peduncle arising from the ground level in acaulescent plants, i.e., a leafless stem of a flower cluster. The flower stem arises from the ground. Plants with such flower growth are said to be "scapose". See Micranthes oregana and Micranthes rhomboidea.

Scapose: See "scape" immediately above.

Scarious: Thin, dry, and membranous in texture, not green. Used in describing the texture/color of some phyllaries. Cirsium scariosum and Vesper spp.

Scientific Name: A two part Latinized name assigned by botanists to plants and accepted internationally. Examples: Ipomopsis ramosa, Linum lewisii, Iris missouriensis, Populus deltoides. The two words (the genus and the specific epithet) describe a plant's characteristics, or honor a person, or commemorate a place, or describe a relationship between plants, etc.

The "scientific name" is also commonly and acceptably referred to as the "Latin name". Even if the name is partly or completely of Greek origin, the name is still referred to as the "Latin name" (or "scientific name").

Scientific names shown in bold on this website are the currently accepted names according to John Kartesz's Biota of North America Program.  Scientific names shown in normal font are synonyms.

See Plant Names for a discussion of why we should use scientific not common names, how scientific names are arrived at, a brief history of the development of scientific names, and why scientific names change.  Very interesting.  

Also see Genus, Species, Synonyms.

Scopulorum: Of rocky places.

Scree: Fields (often extensive) of small (often one or two feet on a side and an inch to a foot thick), loose, slab rock.  Such loose rock fields are very common above 11,000 feet in the San Juans. Larger boulder fields are called "talus" but the two terms grade into each other.

Secund: Growing to one side, not surrounding the stem. Frequently used in describing flowers or fruits that all grow pointing to one side of the stem. Secund flowers and fruits either bend to or emanate from one side of the flower stem.  See Solidago velutina, Orthilia secunda, and Penstemon strictus.

Semi-deserts: From 5,000 to 6,500 feet in the Four Corners area.  Arid.  Annually 7-14 inches of moisture, 1/4 or less from snow.  Semi-desert areas are characterized by open, sandy flats with scattered shrubs (Saltbush, Sagebrush) and Cottonwoods along washes.  Higher semi-desert flats and canyons have Pinyon Pine, Juniper, and Oak with some thick patches of Sagebrush, Yucca, Mountain Mahogany, and other shrubs.  Wildflower growth is best from March to June but is highly dependent on winter moisture.

Sepal: One of the segments of the calyx, the outermost whorl of the perianth. The calyx encloses and protects the other floral parts when the flower is in bud, and then opens and subtends or surrounds the petals and sexual parts.  In most flowering plants, there are sepals and petals. If there is just one whorl of external floral parts, they are called sepals. If the sepals and petals are of the same shape, size, color, and texture, they are called "tepals", instead of sepals and petals.

As they mature, sepals may have petals curved back through them; they may alternate with the petals; they may be smaller than or larger than the petals; etc.  Typically they are smaller than the petals and are green, not showy. See
Mitella stauropetala and Ceanothus fendleri.  Sepal numbers, shapes, sizes, etc. are highly variable. In relatively few flowers, sepals are quite attractive, as they are in the Colorado state flower, Aquilegia coerulea (Columbine).

Septum: A partition, e.g., the partitions in an ovary that separate the locules.

Sericious: Silky, as in hairs.

Serrate: Saw-like; with forward pointing teeth along the margin, as in some leaves.

Sessile: Lacking a stem. Flowers and leaves can be attached to their main stalk with or without a stem.

Setae: Short, stiff hairs. Bristles. Singular is "seta".

Setose: Covered with bristles. "Setaceous" means bristle-like.

Shrublands: Arid lands characterized by shrubs, grasses, and a lack of trees.

Silicle: A fruit of Brassicaceae (the Mustard Family) which is typically less than twice as long as wide, often round and flat. See silique below.  Alyssum parviflorum.

Silique: A fruit of Brassicaceae (the Mustard Family) which is typically more than twice as long as wide. See silicle above.
Some floras dispense with the differentiation made between these two terms and call all Brassicaceae fruits, "siliques".  Descurainia spp.  Boechera spp

Simple: The leaf blade is not divided into separate leaflets. See leaf type.

Sinus: A cleft, indentation between lobes, as in the indentations on an oak leaf.  Quercus gambelii.

Sori: The dots on the back of fertile fern fronds.  These sori are actually groupings of many individual sporangia, each of which encloses numerous spores (the reproductive bodies of ferns). Polystichum lonchitis.

sp.: Abbreviation for "species".  (Plural is "spp.".) These abbreviations are most often used to indicate that the exact species is unknown, e.g., "Aster sp." would mean that the author is confident the plant is in the Aster genus, but the author does not know exactly which species it is.  You might use "spp." to label the plants in a photograph when there are a number of different species of the same genus but they have not been individually identified.

Spatulate: Shaped like a spatula. Usually used in describing a leaf that is round at its tip and has more parallel sides as it tapers to its narrow base. Oblanceolate leaves are also wider at their tip but they are not round at their tip.  Boechera lemmonii.

Species: A single, individual, unique plant. A subdivision of a genus.  A species has sufficient unique characteristics to make it differentiated from all other plants within its genus and thus unique among all other plants in the world. 

It is generally true that one species cannot fertilize another species. Intermountain Flora indicates: "A typical species is separated from other species by an absolute or nearly absolute gap in the variability, and by a complete or nearly complete barrier to interbreeding."

The exact meaning of "species" has, however, been argued for centuries and is still not settled. An 85 year old botanist friend of mine says, "When I was a student I knew exactly what a species was. Now I don't have the foggiest notion!"

In The Origin of Species Darwin says: "Nor shall I here discuss the various definitions which have been given of the term species. No one definition has as yet satisfied all naturalists; yet every naturalist knows vaguely what he means when he speaks of a species.... I look at the term species, as one arbitrarily given for the sake of convenience to a set of individuals closely resembling each other".

The convention which we use for naming plants was developed by Linnaeus in the 1700s. The scientific name for a plant, i.e., the name of the species, is two-part, two words.  The first word designates the genus to which the species belongs and the second word, called the "specific epithet" (or "species epithet"), gives a name to distinguish this plant from all others in the same genus.  For example, in the name Senecio serra, "Senecio" is the genus and "serra" is the specific epithet. There are many other Senecios but only one Senecio serra  --  in the entire world.  

Both the genus and the specific epithet are italicized; the genus is capitalized and the specific epithet is lower case Senecio serra. 

Identifying the species is more complicated than identifying the family or genus and requires careful examination of the entire plant utilizing a magnifying glass and detailed botanical texts. 

Scientific names shown in bold on the enlarged photo pages of this website are the names accepted by John Kartesz in his Biota of North America Program, his labor of 55 years. Scientific names shown in normal font are synonyms. See Family, Genus, Scientific Name, Plant Names, and Synonyms.

Specific epithet: Scientific names consist of two parts, the genus name and the specific epithet. In the name, "Geranium richardsonii", "Geranium" is the genus and "richardsonii" is the specific epithet.  Frequently the specific epithet is incorrectly called the "species", i.e., it is incorrect to say that "richardsonii" is the "species".  The species is Geranium richardsonii.

Speciosus: Showy, as in, Erigeron speciosus.

Spike: An elongated type of inflorescence in which each flower is sessile, i.e., attached to the stem directly without itself having a stem (a "pedicel"). See Elephant Heads for an example of a spike.

Spiraled: See leaf position.

Sporangia: See "Sori".

Spores: See "Sori".

Sporophore: The fertile, spore-bearing portion of a Botrychium leaf. See "trophophore".

Spreading: Diverging, extending horizontally, as in branches, petals, hairs, etc. See divergent. Contrast appressed and ascending.

spp.: See "sp.".

Squarrose: Recurved.

ssp.:  Subspecies.  Also "subsp.".  Literally, "almost a species".  See "var.".

Stamen: The pollen producing part of the flower. See carpel.

Staminate: Having only male, pollen producing floral parts. See pistillate.

Staminodes: Sterile stamens. See Parnassia parviflora.

Stellate: Star-like, as in hairs that have multiple branches and appear like a star-burst. Draba spp.

Stigma: The top of the pistil to which pollen can adhere.

Stipule: An often papery appendage, commonly leaf-like, usually occurring in pairs at the base of the petiole of a leaf. See Spergularia rubra.

Stolon: A slender modified stem running along the ground, rooting at the tip, and sprouting new plants. Strawberries have stolons. See Fragaria spp and  Erigeron flagellaris.

Streamsides: Moist areas along streams.

Strigose: With short, sharply pointed, stiff, appressed hairs. Erigeron argentatus.

Sub: Almost, as in subequal, subalpine, subentire, subcylindric, subcapitate.

Subalpine: From 10,000 to 11,500 feet.  Characterized by thick Spruce/Fir forests; Aspens grow at lower elevations in this zone.  Annually about 25-40 inches of moisture, most from snow (about 250-350 inches).  Lush wildflower growth mid-June through August.

Subsp: Abbreviation for subspecies.  Also "ssp.".

Subspecies: A taxonomic category below species, i.e., a division of species into two or more units each of which is clearly the same species but distinct enough from each other in some characteristics to be differentiated from each other. These small but obvious differences are the result of geographic separateness whereas varieties of a species or subspecies usually exist in the same geographic area. Abbreviated subsp. or ssp.

It is often difficult for professional botanists to determine whether a taxon should be called a subspecies or a variety.

The Kew Gardens "Plants of the World Online" indicates that the classification of "subspecies" is given if the , "distribution range [is] separate (so that non-overlapping rings can be drawn round them on a map) or nearly so, gene flow absent or very restricted between the infraspecific populations and differing in characters that are significant for taxonomic species differentiation within the genus".

The term "variety" is used when "Distribution ranges overlapping, gene flow possible and not differing in characters that are significant for taxonomic species differentiation within the genus".

Subtend: Below and close to as in, "bracts subtend the inflorescence".

Sulcate: Grooved.

Sunflower Family: See Asteraceae.

Superior: Hypogynous. Attached above. Commonly used to describe the position of a flower's ovary in relation to the point of attachment of the petals and sepals. A superior ovary is above the point of attachment of the sepals and petals. Contrast with inferior. The term has nothing to do with the quality of the ovary; the term does not mean "of greater value".   Arnica mollis.

Sympatric: Occupying the same geographic region.

Synonym: An outdated plant name. "Synonym" in botany does not have the same meaning as it does in the daily use of the English word, i.e., a synonym is not a word that can be used as a substitute for a similar word. In botany a synonym is a species name that at one time was thought to be the correct name for a plant but was later found to be incorrect and was replaced by a new name.

For a number of reasons (see Plant Names), a species might acquire several scientific names. It is common for several of these names to be in use at the same time. This happens because there is no organization (such as there is in the birding world) that determines which name should be used and which names are synonyms. Each botanist makes this determination based on the authorities and research they accept. Botanists believe that agreement on one name will be reached over time. Fortunately a search of botanical literature and floras often shows that most botanists do favor one of the names.

In some instances I may list a name as a synonym even though that name is still appropriately in use. How can that occur? Take Erigeron peregrinus as an example. That name was used for nearly two centuries for a species in the Four Corners area (and other areas), but research toward the end of the 20th century showed that Erigeron peregrinus is confined to the very northwestern areas of North America (where it was discovered around 1800). The very similar species, E. glacialis (discovered in Wyoming around 1830) is widely spread through the West. Somehow the species of our area was confused with the species of the northwest. When that mistake became known, our species was renamed E. glacialis and E. peregrinus became a synonym -- for us in the Rocky Mountain area.

Both Erigeron names are still legitimate names for plants of two different locations in North America. Other examples of this use of the word "synonym" are Penstemon lentus and Penstemon osterhoutii; Penstemon crandallii and Penstemon caespitosus; Potentilla concinna and Potentilla bicrenata.

On this website I use plant names listed in the Taxonomic Data Center of BONAP by national plant authority John Kartesz.  BONAP names are in bold. Synonyms are not bold.

Click "Plant Names" for more information about how plants are named, how plants acquire a number of names, more details about synonyms, the complexity of naming plants, etc.

Taxa: Plural of "taxon".

Taxon: A biologic entity, such as, a genus, species, subspecies, or variety. The state flower of Colorado, Aquilegia coerulea, is one taxon.

Taxonomy: The ordering of plants and animals according to established criteria.

Tepals:  A handy term used to designate the segments of the perianth (the sepals and the petals) when these are very similar in size, shape, color, and texture, i.e., when they are "undifferentiated", which is the word used by many botanical glossaries to define "tepals": "Tepals are undifferentiated sepals and petals". However, if one looks carefully at tepals, one can see that they arise from outer (sepal) and inner (petal) growth points and actually can be differentiated.

The term, "tepals" is not used by some prominent floras; those floras use the terms "sepals" and "petals". Also, the term "tepals" is used with different meanings by some prominent floras.

See Erythronium grandiflorum, Opuntia, and Eriogonum hookeri

Terete: Round in cross section, cylindrical.

Ternate: Grouped into threes, as in a leaf divided into three leaflets, (for which the term "trifoliate" would be even more specific). Lomatium triternatum.

Throat: A tubular corolla's slightly or significantly bulged or widened section that is found between the evenly elongated tube and the limb (the expanded, often lobed, tip of the corolla). See Penstemon comarrhenus. Not all tubular corollas have a widened throat; the tube can be evenly elongated to the limb. Not all floras use this term.

Thyrse: A compact, compound panicle often so thickly flowered that the main stem is obscured.

Tomentose: Densely clothed with matted, woolly hairs. See the very similar terms, lanate and villous.

Trichome: A general term for plant hair.

Trifoliate: With three leaves or three leaflets. See "ternate". Trifolium brandegeei and T. parryi.

Trophophore: The sterile, leaf-like portion of a Botrychium leaf. See "sporophore".

Tube: The evenly elongated lower section of a flower that has united petals. The tube sometimes expands into a throat which is topped by the limb (the expanded, often lobed, tip of the corolla). See Ipomopsis ramosa for a tube and limb.

Tubercle: An expanded structure common on some Cacti.  See Escobaria vivipara for close-up photographs of tubercles.

Tundra: Land above tree line characterized by a short growing season, intense sun and wind, thin soils, very high snow fall and high rain fall, and low growing sedges, grasses, dwarf shrubs, and dwarf herbs.

Turbinate: Top-shaped, inversely conical. Eriogonum cernuum.

Turions: Minute. rosebud-like shoots on the roots or at the base of the stems of some aquatic or semi-aquatic plants, such as, Epilobiums.

Type or type specimen: The first plant of its kind collected for science, submitted for classification purposes, and stored in an herbarium.  There are various types: The "holotype" is the one specimen that the first description and name are based on.  An "isotype" is a specimen collected at the same time as the holotype by the same person.  A "lectotype" is a specimen later designated as the type specimen when no holotype was originally designated. See "Type Locality" immediately below.

Type locality: Refers to the location where the type specimen was collected.  See "Type or Type Specimen" immediately above.

Umbel: A type of inflorescence in which each pedicel/peduncle, i.e., each flower or flower cluster stalk, grows upward and outward from one point in the same manner the spokes of an umbrella spread upward and outward from the umbrella main stem. The resultant flower cluster has a rounded top versus corymbs which have a flattened top. See Apiaceae (Umbelliferae) for examples. Cow Parsnip and Loveroot.

Compound umbels start with the pedicels originating from the same point and then branching again before a flower grows at the tip of each branching.

Corymb inflorescences are very similar to umbels but their pedicels do not originate from the same point on the main stem.

Unisexual: A flower with either stamens or pistils, but not both. Imperfect.

var.:  Variety.

Variety:  A taxonomic subunit of a species or subspecies. Varieties of a species or subspecies are distinct because within the main area of distribution of that taxon there are some small variations in form, color, habit, etc. This contrasts with "subspecies" which is geographically separated from the main area of distribution of the taxon and there are more pronounced differences between the subspecies and the main population.

Some botanists believe that only one term, "subspecies" or "variety" should be used. It is also common to find one botanist calling the plant a subspecies while another calls it a variety. Some botanists maintain that neither term should be used. See subspecies. 

Vegetation Zone (elevation): As used in this website, "vegetation zone" refers to those elevations in which a plant best survives.

Alpine: Above 11,500 feet (tree line). Characterized by tundra: land of thin soil, rocks, a very short growing season, and frost any day of the year.
Subalpine: From 10,000 to 11,500 feet. Characterized by thick Spruce/Fir forests. Aspens grow at lower elevations in this zone.
Montane: From 8,000 to 10,000 feet. Open Aspen forests, sometimes with heavy undergrowth of shrubs (Snowberry, Currants, Elderberry). Colorado Blue Spruce in moist areas. At lower elevations some large stands of Ponderosa Pine with scattered Douglas Fir on north facing slopes.
Foothills: From 6,500 to 8,000 feet (lower along the Front Range). Composed of Pinyon Pine, Juniper, and Oak forests, often quite thick. Pockets of Douglas Firs. Ponderosa Pine at higher elevations. Numerous shrubs.
Semi-deserts (or Prairie on Front Range): From 4,000 to 6,500 feet. Arid. Annually 7-14 inches of moisture, 1/4 or less from snow. Semi-desert/prairie areas are characterized by open, sand/gravel flats with scattered shrubs (Saltbush, Sagebrush) and Cottonwoods along washes. Higher semi-desert flats and canyons have Pinyon Pine, Juniper, and Oak with some thick patches of Sagebrush, Yucca, Mountain Mahogany, and other shrubs.

Ventral: The top side, as in the upper surface of a leaf. Adaxial. See dorsal.

Verticil (verticillaster): A whorl of parts about a central axis. See Marrubium vulgare.

Villous: Clothed with long, soft, unmatted hairs. See the very similar terms, lanate and tomentose.

Viscid: Sticky.

Vivaparous: Bearing live off-springs, i.e., in plants, reproducing from bulblets that grow on the parent plant and then drop to the ground to begin growing anew. Such plants may not reproduce at all, or may reproduce in addition to reproducing from seeds. Lithophragma glabrum  Bistorta vivipara.

Vulgaris: Common.

Wetlands: Wet meadows, fens, seeps, etc.

Whorled: See leaf position.

Winter Annual: A plant that germinates in the fall, over-winters, and then in the next year, grows in the spring, flowers, sets seeds, and dies.

Woodlands: Forested areas.

Woody: A plant whose stems become increasingly large and stiff with added years of growth. Not herbaceous, not soft and pliable, not dying back to the ground yearly.

The woody accumulation provides strength, protection for vital plant parts, and increased leaf production.  The latter ability allows for increased oxygen production and thus our existence.  Knock on wood!  See Herb.

Zygomorphic: Asymmetric. An irregular flower, one that is bilaterally symmetrical. Such a flower can only be divided in one way to produce mirror images. Penstemon spp. Contrast to actinomorphic (regular).

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