Astragalus crassicarpus var. crassicarpus

Native

Prairies, roadsides

April to May

Purple

Reclining, 4″ to 24″ long

This is a 1″ to 6″ tall, reclining, perennial forb rising on a cluster of stems from a stout taproot and caudex.

The stems recline on the ground with the tips turned upward. They can extend 4″ to 24″ but are usually no more than 15″ long. They branch near the base but are otherwise mostly unbranched. They are covered with straight, stiff, appressed hairs.

The leaves are alternate, 2″ to 5″ long, and pinnately divided into 15 to 29 leaflets. Each leaf has a terminal leaflet and an odd total number of leaflets. There is an egg-shaped, pointed, ⅛″ to ⅜″ long stipule at the base of each leaf stalk.

The leaflets are inversely lance-shaped to elliptic, 5 ⁄16″ to ⅝″ long, and less than ¼″ wide. The leaf tips may be rounded or pointed. The upper surface is sparsely covered with appressed hairs or is hairless. The lower surface is covered with appressed hairs.

The inflorescence is an unbranched, short cluster of 5 to 25 stalked flowers. It is on a stout, 1″ to 4″ long stalk rising from a leaf axil. The stalk is equal to or shorter than the leaves.

The flowers are ⅝″ to 1″ long. There are 5 sepals fused for most of their length into a ¼″ to 5 ⁄16″ long, cylinder-shaped calyx tube with dark hairs. The 5 petals are purple and form a butterfly-like corolla, as is typical of plants in the Pea family. They are organized into a broad banner petal at the top, two lateral wing petals, and between the wings two petals fused into a keel. The banner is broad, ½″ to 1″ wide, and is notched at the tip.

The fruit is a ½″ to 1″ long, purplish-brown seedpod containing many seeds.

American vetch (Vicia americana ssp. americana) stems are hairless. The leaves are hairless or sparsely hairy. Each leaf has just 4 to 8 pairs of leaflets. There is a tendril in place of the terminal leaflet, giving the leaf an even number of leaflets. The leaflets are larger, up to 1″ long and ½″ wide. The inflorescence has just 2 to 9 flowers.