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    Epilobiums are often difficult to identify because there is, as Intermountain Flora states, "rampant hybridization in... Epilobium". Intermountain Flora also indicates that in about half of the species in our area, "specific distinctions are... vague".

    Linnaeus named this genus in 1753. The word "Epilobium" is from the Greek for "upon a capsule" and refers to the long tubular inferior ovary, shown extending to the left of the pinched area in the center of this photograph of Epilobium ciliatum.

Epilobium ciliatum
Epilobium anagallidifolium
Epilobium anagallidifolium. Synonym: Epilobium alpinum. (Alpine Willowherb)
Onagraceae (Evening Primrose Family)

Montane, subalpine, alpine. Wet areas, tundra. Summer.
Stony Pass above Silverton, July 21, 2012.

Epilobium anagallidifolium grows from 1 to 9 inches tall, somewhat mat-forming, with a number of stems, these often curved to S-shaped. Leaves are sessile or short-petioled, ovate to oblanceolate, to a bit over an inch long. Some floras indicate that the leaf shape varies according to the position on the plant: basal = spatulate to oblong, mid-stem = elliptic, and above = lanceolate or nearly linear. Other floras simply indicate that the leaf shape varies. Weber indicates that the plant has turions (fleshy winter buds at base of stem), other floras indicate there are no turions.

E. anagallidifolium is similar to E. hornemannii (shown below) differing by its smaller stature, nearly entire leaves, and shorter capsule.

Jean Baptiste Lamarck named this species in 1786 from collections made in France.  The specific epithet is from a Greek plant name which later was given to plants in the genus Anagallis (Pimpernel), Primulaceae (now often Myrsinaceae). Thus the specific epithet means, "with leaves similar to Anagallis".

Several botanical experts consider E. anagallidifolium more appropriately named E. alpinum.

 

Epilobium anagallidifolium
Epilobium anagallidifolium. Synonym: Epilobium alpinum. (Alpine Willowherb)
Onagraceae (Evening Primrose Family)

Montane, subalpine, alpine. Wet areas, tundra. Summer.
Fen near Taylor Mesa Road, July 24, 2015.

Buds often nod; flowers are erect. Flower color is pink to purple to rarely white. Flowers usually remain open for several days.

 

 

Epilobium anagallidifoliumm
Epilobium anagallidifolium. Synonym: Epilobium alpinum. (Alpine Willowherb)
Onagraceae (Evening Primrose Family)

Subalpine, alpine. Wet areas, tundra. Summer.
Fen near Taylor Mesa Road, July 24, 2015.

 

 

 

Epilobium brachycarpum
Epilobium brachycarpum
Epilobium brachycarpum
 
Epilobium brachycarpum. Synonym: Epilobium paniculatum. (Short Fruit Willowherb)
Onagraceae (Evening Primrose Family)

Foothills, montane. Disturbed areas, woods, grasslands. Summer.
Above: Near Roaring Fork Road, August 5, 2020 and Far western San Juan National Forest, July 17, 2020.
Left: Rough Canyon Trail, July 1, 2020.

Epilobium brachycarpum is a very slender annual that grows from just 8 inches to 80 inches tall, often with dozens of other E. brachycarpum plants scattered around it. Stems are single, typically with opposite leaves below and alternate above. Leaves are sparse, commonly reduced in size upward, often folded along the midrib, and sometimes in small bundles upward on the stem. As the photograph directly above indicates, small Epilobium brachycarpum can be very difficult to pick out from its normal grass and other forb companions, but as the top photograph shows, the plant is easier to see as it grows taller.

This species stands out from other Epilobium in that it is annual, has a limited elevational range, has a taproot, and its stem has peeling bark just above ground level.

The species was named and described by Carel Presl in 1831 from a collection made in Mexico in the early 1800s by T. P. Haenke.

"Brachycarpum" is Greek for "short fruit".

Epilobium brachycarpum

Epilobium brachycarpum. Synonym: Epilobium paniculatum. (Short Fruit Willowherb)
Onagraceae (Evening Primrose Family)

Foothills, montane. Disturbed areas, woods, grasslands. Summer.
Rough Canyon Trail, July 1, 2020.

Flowers are erect above an elongated inferior ovary. Flower color is white to pink to purple. Petals are just 2-6 mm long.

 

 

Epilobium brachycarpum

Epilobium brachycarpum

Epilobium brachycarpum

Epilobium brachycarpum. Synonym: Epilobium paniculatum. (Short Fruit Willowherb)
Onagraceae (Evening Primrose Family)

Foothills, montane. Disturbed areas, woods, grasslands. Summer.
Rough Canyon Trail, July 1, 2020 and far western San Juan National Forest, July 17, 2020.

Four dainty flower petals range from 3-8 mm long and are deeply notched. Seed capsules range from 1.3 to 3 cm long.

Epilobium brachycarpum

Epilobium brachycarpum. Synonym: Epilobium paniculatum. (Short Fruit Willowherb)
Onagraceae (Evening Primrose Family)

Foothills, montane. Disturbed areas, woods, grasslands. Summer.
Rough Canyon Trail, July 1, 2020.

The very unusual peeling bark just above ground level helps to quickly identify this Epilobium species.

 

 

Epilobium ciliatum
Epilobium ciliatum
Epilobium ciliatum (Fringed Willowherb)
Onagraceae (Evening Primrose Family)

Foothills, montane. Roadsides, meadows. Summer.
Above: Dolores/Norwood Road, August 16, 2021.
Left: Prater Ridge Trail, Mesa Verde National Park, August 13, 2005.

As the map below indicates, Epilobium ciliatum is widely distributed throughout the West. Utah Flora expert, Stanley Welsh, indicates that it is the most common species of Epilobium in Utah, "almost ubiquitous along streams, lake margins, irrigation canals, and near seeps and springs." It can be 8 to 48 inches tall and is variable in leaf shape, amount of branching of the stem, and other characteristics.  Even the silky fluff that carries the seeds can vary from white to dingy.

The picture at left shows just the lower few inches of a plant over two feet tall.  Leaves are very minutely toothed and stems often reddish.  

Constantine Rafinesque named this species in 1808.  The species has had several dozen other names since then.  "Ciliatum" is Latin for "hairy" and botanically refers to fine, marginal hairs  --  which can be seen as a silvery glow along the edges of some of the seed pods and buds in the photograph above and the two photographs below.

 

Epilobium ciliatum
Epilobium ciliatum (Fringed Willowherb)
Onagraceae (Evening Primrose Family)

Foothills, montane. Roadsides, meadows. Summer.
Prater Ridge Trail, Mesa Verde National Park, August 13, 2005.

Pink flowers are most common for Epilobium ciliatum but white is almost as common and both pink and white flowers can appear on the same plant.

Epilobium ciliatum

Epilobium ciliatum

Epilobium ciliatum (Fringed Willowherb)
Onagraceae (Evening Primrose Family)

Foothills, montane. Roadsides, meadows. Summer.
Prater Ridge Trail, Mesa Verde National Park, August 13, 2005 and near Yellow Jacket Canyon, September 5, 2014.

The long, vertical seed pods    Epilobium ciliatum

ripen and split in graceful arches exposing the soft tuft of hairs that are attached to and carry aloft the tiny (1+ mm) brown, minutely ridged seeds. The minute ridges (conspicuous only under high magnification) actually are long rows of dozens of papillae.

The typical wetland location of this species, its tendency to be quite tall and branched, its parallel ridged seeds, and the presence of quite small serrations on the leaf margins, all help identify this species. E. ciliatum subspecies glandulosum is further distinguished by the presence of turions, minute, rosebud-like shoots on the roots or at the base of the stems.

 

Epilobium hornemannii (Hornemann's Willowherb)
Onagraceae (Evening Primrose Family)

Montane, subalpine. Meadows, streamsides. Summer.
Kilpacker Trail, August 1, 2000.

Epilobium hornemannii is a common and highly variable plant. Epilobium hornemannii flowers are tiny, pink/white/light-blue, and inconspicuous, but the plant is so common that it eventually attracts attention.  The pictured specimen is lush; other Epilobium hornemannii (see below) may have far fewer and narrower leaves, fewer stems, and be shorter.

Exact identification is sometimes quite problematic since, as observed above, it also hybridizes .  For instance, E. Hornemannii hybridizes readily with E. lactiflorum which occupies similar habitat as E. hornemannii and, according to William Weber, can be distinguished from E. hornemannii primarily by its "several broad withered leaves [at the base of the stem] at flowering time."  E. hornemannii has "small and inconspicuous or no withered leaves" at flowering time.

Look for Epilobium hornemannii along moist montane and sub-alpine trails, near ponds, and along irrigation ditches.  It is common for Epilobium hornemannii to have red stems and leaves in the spring and to return to these colors in the fall.

Heinrich Reichenbach (1793-1879) named this species in 1824.  Jens Hornemann was a Danish botanist of the early 1800s. (More biographical information about Hornemann.)

Epilobium hornemannii
Epilobium hornemannii (Hornemann's Willowherb)
Onagraceae (Evening Primrose Family)

Montane, subalpine.  Meadows, streamsides. Summer.
Groundhog Meadow Trail, July 31, 2004.

Epilobium hornemannii
Epilobium hornemannii (Hornemann's Willowherb)
Onagraceae (Evening Primrose Family)

Montane, subalpine.  Meadows, streamsides. Summer.
Groundhog Meadow Trail, July 31, 2004.

Epilobium hornemannii
Epilobium hornemannii  (Hornemann's Willowherb)
Onagraceae (Evening Primrose Family)

Montane, subalpine.  Meadows, streamsides. Summer.
Colorado Trail near Kennebec Pass, August 12, 2004.

Epilobium hornemannii
Epilobium hornemannii (Hornemann's Willowherb)
Onagraceae (Evening Primrose Family)

Montane, subalpine.  Meadows, streamsides. Summer.
Colorado Trail near Kennebec Pass, August 12, 2004.

Epilobium hornemannii seed capsules (the dark vertical tubes in the lower and upper right) split in graceful arches (center) and the brown seeds imbedded in tiny white fluff are ready for a breeze.

Epilobium hornemannii
Epilobium hornemannii (Hornemann's Willowherb)
Onagraceae (Evening Primrose Family)

Montane, subalpine.  Meadows, streamsides. Summer.
Ryman Creek Trail, August 30, 2013.

Epilobium hornemannii puts on quite a show in wetlands where it can grow in thick clumps with numerous flowers that ripen and erupt with a fluff of seeds.

Range map © John Kartesz,
Floristic Synthesis of North America

State Color Key

Species present in state and native
Species present in state and exotic
Species not present in state

County Color Key

Species present and not rare
Species present and rare
Species extirpated (historic)
Species extinct
Species noxious
Species exotic and present
Native species, but adventive in state
Eradicated
Questionable presence

Epilobium anagallidifolium

Range map for Epilobium anagallidifolium

Epilobium brachycarpum

Range map for Epilobium brachycarpum

Range map for Epilobium ciliatum

Range map for Epilobium hornemannii