All the Chickweeds shown share Alsinaceae characteristics: small, bright, white flowers and narrow, long, opposite leaves.  Chickweeds generally are matted quite low to the ground, but several do grow to a slender 20 inches.

    The family name, "Alsinaceae", is the ancient Greek name for similar plants.

    The 2005 Flora of North America, the Synthesis of the North American Flora, the on-line USDA Plant Database, the Intermountain Flora, and A Flora of Utah all place the following plants in Caryophyllaceae (Pink Family).  Weber places them in Alsinaceae.

Montane, subalpine. Open woodlands. Summer, fall.
Horse Creek Trail, August 31, 2005.

Spergulastrum lanuginosum sprawls along the ground making very loose, open mounds with 3-7 inch stems topped by bright white flowers.  Rounded white petals are slightly longer than the pointed green sepals and the pink anther stamens are arched back over the petals:

Look for this common Chickweed along trails through open Spruce forests.  What you will notice first are the bright white flowers.

The Flora of North America indicates that this species "is morphologically diverse... and is in serous need of comprehensive study."

The Spergulastrum genus was named by Michaux in 1803 and Michaux also was the first to name this species, "lanuginosum".  Spergula is another genus of the Chickweed Family, and "astrum" is, according to Weber, a Latin suffix for "related".  "Lanuginosum", from the Latin for "wool" and "full of", perhaps refers to the densely hairy leaves and stems.    Weber added "subspecies saxosum".

Linnaeus named the Arenaria genus in 1753 and Paul Rohrbach (1846-1871) posthumously renamed Michaux's Spergulastrum lanuginosum to Arenaria lanuginosa in 1872.  The Flora of North America places this species in the Arenaria genus, as does the Synthesis of the North American Flora and A Utah Flora.

Foothills to alpine. Meadows, moist areas. Summer, fall.
Horse Creek Trail, August 31, 2005.

Stellaria longipes grows to a very slender four-to-eight inches.  It enjoys open meadows, dry forests, and wet areas and thrives from the foothills to the alpine zones.  Its leaves are narrow, cupped, and lustrous green, generally angling upward.  Flower petals (white in the picture below) are deeply cut and about twice as long as the sepals (green, behind the white petals).

The genus name, Stellaria, is Latin for "star" and was given by Linnaeus in 1753.  "Longipes", a name given by John Goldie (1793-1886), perhaps is from the Latin for "long worm" referring to the plants very skinny stature.

Subalpine, alpine. Scree, tundra. Summer.
Lizard Head Trail, August 18, 2005.

Tryphane rubella reclines upon the ground as if it were wind-swept -- and it does usually grow in alpine windy areas, but its prostrate position is just the way it enjoys growing.  The reclining stems are about one-to-four inches long (those pictured are two inches) and a typical plant is about four inches in diameter.  Bright white, five-petaled flowers turn upward at the end of the stems.  The tiny 1/4 to 1/3 inch stiff, three veined leaves are in about four clusters evenly spaced on the stem.  Since the plant is only about an inch high, it is very easy to pass by.  Don't.  Get down to its level and marvel at its beauty.

"Tryphane" is Greek for "delicate" and "rubella" is Latin for "somewhat red" referring to the stem color, most evident in the bottom center of the next picture.

Tryphane rubella is circumpolar and is found from the Arctic at sea level to 12,000 foot alpine ridges.  It is found in all western states and in all Canadian provinces.

The plant was first named Alsine rubella in 1812 by George Wahlenberg (1780-1851), Weber accepts Heinrich Gottlieb Reichenbach's (1793-1879) 1841 name of Tryphane rubella, and The Flora of North America and Synthesis of the North American Flora accept William Hiern's (1839-1925) Minuartia rubella designation of 1899. 

Subalpine, alpine. Scree, tundra. Summer.
Lizard Head Trail, August 18, 2005.