2.

Asclepias hirtella (Pennell) Woodson (prairie milkweed, tall green milkweed)

Acerates hirtella Pennell

Asclepias longifolia Michx. ssp. hirtella (Pennell) J. Farmer & C.R. Bell

Pl. 221 c–e; Map 916

Plants with white latex and a thickened woody rootstock. Stems 25–110 cm long, sometimes few-branched toward the tip, mostly erect or ascending, moderately to densely short-hairy, sometimes in longitudinal lines, with numerous nodes. Leaves mostly alternate, sessile or short-petiolate. Leaf blades 4–17 cm long, 0.3–1.5 cm wide, linear to narrowly lanceolate, the base narrowed or tapered, the tip tapered gradually to a sharp point, the margins flat, sparsely to moderately rough-pubescent with short, stiff hairs, especially along the veins and margins. Inflorescences (1)2–10 in the leaf axils, short-stalked or sometimes appearing sessile, with 25–90 flowers. Calyces reflexed, hairy on the outer surface, the lobes 1.5–3.0 mm long, lanceolate to ovate. Corollas reflexed, glabrous, green to pale green, usually somewhat purple-tinged, the lobes 4–6 mm long, elliptic-lanceolate. Gynostegium appearing stalked (the column visible below the bases of the hoods), pale green, the corona noticeably shorter than the tip of the anther/stigma head. Corona hoods 1.5–2.5 mm long, erect, attached most of their length, oblong-elliptic in outline, the opening oriented toward the column, the tips broadly rounded to truncate, the margins not toothed, the bases pouched. Horns absent. Fruits 7–14 cm long, erect or ascending from usually deflexed stalks, lanceolate to narrowly ovate in outline, the surface smooth, minutely hairy. Seeds with the body 7–9 mm long, the margins relatively broadly winged, the terminal tuft of hairs white or more commonly light cream-colored to tan. May–August.

Scattered, mostly in the Glaciated Plains and Unglaciated Plains Divisions; absent from the Mississippi Lowlands (West Virginia to Minnesota, Iowa, and Kansas south to Tennessee, Arkansas, and Oklahoma; Canada). Bottomland and upland prairies and glades; also pastures, roadsides, and railroads.