Asclepias cooperi N.E.Br.

Plant 1/2-1 ft. high, probably branching at the base; stems often decumbent below, bifariously subscabrous to subhispid; leaves 5-7 pairs to a stem, ascending or somewhat spreading; petiole 2-6 lin. long; blade 1 1/2-3 in. long, 1/4-1/2 in. broad, lanceolate, cuneate or cuneately subhastate to subtruncate at the base, thence tapering to the acute apex, undulate at the scabrous margins, harshly pubescent with rather coarse hairs on both sides; umbel solitary, terminal, 1 1/2-2 in. in diam., semiglobose, 30-50-flowered; peduncle 2-4 in. long, subscabrous to thinly subhispid; bracts about 2 lin. long, subulate, pubescent; pedicels 6-8 lin. long, thinly and somewhat harshly to densely and softly villous; sepals about 1 1/2 lin. long, lanceolate, acute, thinly hairy; corolla-lobes reflexed, with upcurved tips, 2 1/2-3 lin. long, 1 1/2 to nearly 2 lin. broad, elliptic-oblong, subacute, most minutely puberulous at the base of the inner face, otherwise glabrous or with a few hairs near the apex on the back, apparently greenish-yellow, tipped with purple-brown on the back; corona-lobes arising about 1/2 lin. up the staminal column, erect, fleshy, complicate-cucullate, 1 1/4-1 1/2 lin. long, about 1 lin. broad across the side of the obliquely truncate top, which is slightly highest at the dorsal apex, rounded in to the narrowed base at the back, in side-view somewhat oblong with a very short obliquely claw-like base, the inner margins produced at the top into short horizontal deltoid acute teeth, entirely deep-yellow; staminal column 1-1 1/3 lin. long; anther-appendages subreniform, obtuse, inflexed upon and concealing the truncate style-apex; anther-wings remarkably prominent, angular at the middle.