Kansas Wildflowers and Grasses

SPIDER MILKWEED

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Asclepias viridis Walt.

Tallgrass Prairie National Preserve,

Perennial

Height: 8-26 inches

Family: Apocynaceae - Dogbane Family

Flowering Period: May, June, July

Also Called:

Green antelopehorn.

Stems:

Ascending, 1-2, simple or sparingly branched above, glabrous or sparsely pubescent above.

Leaves:

Mostly alternate, simple, short-stalked, ascending to spreading, ovate-lanceolate, 2 to 5 inches long, 1/2 to 2 inches wide, glabrous or sparsely fine hairy; margins entire; tips pointed, rounded or notched.

Inflorescences:

Umbels, 1-7, 3 to 5 inches wide, short-stalked, 3-18-flowered, terminal.

Flowers:

5-parted, about 1/2 inch tall, on stalks 1/2 to 1 inch long; calyx lobes lanceolate, green to purple-tinged, minutely pubescent; corolla lobes elliptic-lanceolate, pale green, glabrous, curving upward, about twice as long as hoods; hoods club-shaped, purplish; tips arched; horns absent.

Fruits:

Pods, spindle-shaped, 2.5 to 5 inches long, 1/2 to 3/4 inch wide, slightly hairy, erect on downward-curved stalks; seeds broadly egg-shaped, tufted with white or light tan hairs at tips.

Habitat:

Dry prairies, pastures, ditch banks, and disturbed ground, on sandy or rocky limestone soils.

Distribution:

East 2/3 of Kansas.

Comments:

Spider milkweed can become abundant in overgrazed pastures. Formerly treated as Asclepiadaceae - Milkweed Family.

Resembles spider antelopehorn Asclepias asperula

Spider milkweed flower