Al Schneider's Rocky Mountains Plant Descriptions

Rocky Mountain Milkvetch
Astragalus scopulorum
Pea family (Fabaceae)

Rocky Mountain Milkvetch (Astragalus scopulorum) is fairly common in Colorado. It is often a large plant in attractive, multi-stemmed arrangements, with stems up to two feet long. Flowers are nearly an inch long, numerous, in clusters, and yellow/white. It is common for stems to recline along the ground or rise up fairly straight. The Astragalus is one of the largest (nearly 400 species) in North America and it is, therefore, a real challenge to identify exact species. Thomas Porter named this plant in 1874 from a specimen he collected in 1872 and from a specimen Brandegee collected in 1873, both in Colorado. "Scopulorum" means "of rocky places."


©2009 Al Schneider

Description

robust plant with erect or trailing stems to 20" long. Leaves to over 3" long with 15-29 to 2/3" long, to or , thinly hairy to beneath to above. to 5" long. 4-22 flowered, the flowers declined to nodding. short, to almost 1/2" long . Flowers to 1" long yellow/white, can be purple. Pods hanging, , body , straight or curved, to well over 1" long and 1/4" wide, , three-angled.

Field Marks

Tall milkvetch with stems to 2 feet and numerous yellow/white flowers in clusters.

© Al Schneider

oblanceolate -- top wider than bottom

A peduncle is a common stalk of a cluster of flowers.

A perennial plant lives and blooms for many years.

pedicel -- The stem of a single flower.

stipitate -- Having a small stalk.

calyx -- the sepals of a flower, typically forming a whorl that encloses the petals and forms a protective layer around a flower in bud.

In a pea flower the two bottom petals are fused together forming a boat-like structure called the keel. The glumes of grasses may have a sharp projecting ridge like the keel of a boat.

elliptic -- Oval, with no point or a very short point.

A raceme is an unbranched, indeterminate type of inflorescence bearing flowers having short floral stalks along its axis.

genus -- A subdivision of a botanical Family in which all members have a significant number of similar characteristics.

glabrous -- smooth, glossy, having no bristles or hair-like structures. Bald.

leaflets -- Each little leaf-like thing in a compound leaf is a leaflet.

oblong -- Having an elongated form with somewhat parallel sides. Rectangular.