Cooper’s milkvetch

not listed

N4 - Apparently Secure

S4 - Apparently Secure

not listed

UPL - Obligate upland

FACU - Facultative upland

FACU - Facultative upland

Cooper’s milkvetch is a 12″ to 36″ tall, erect, perennial forb rising on a cluster of stems from a taproot.

The stems are more or less erect, branching, leafy, usually hollow, and hairless or nearly hairless.

The leaves are alternate and pinnately divided into 11 to 23 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 oblong to inversely egg-shaped and ⅜″ to 13 ⁄16″ long. The lower surface of the leaf blade is covered with straight, stiff, sharp, appressed hairs.

The inflorescence is several short, unbranched clusters (racemes) of 10 to 20 stalked flowers rising on a stalk from the leaf axils. The stalk and raceme together barely surpass in length the subtending leaf.

The flowers are 7 ⁄16″ to ⅝″ long. There are 5 sepals fused for most of their length into a ⅛″ to 3 ⁄16″ long, cylinder-shaped tube (calyx), then separated into 5 lobes about half as long as the tube. The 5 petals are white to cream colored 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 notched at the tip.

The fruit is an inflated, spindle-shaped or egg-shaped, ⅝″ to ¾″ long, 5 ⁄16″ to 11 ⁄16″ wide seed pod. The pod is stalkless and straight. It is held erect or spreading, not drooping.

12″ to 36″

White to cream

Lake shores, stream banks, river banks. Full to partial sun.

June to July

Sources

2, 3, 4, 5, 7, 28, 29, 30.

Native

Plant

Inflorescence

Leaves