17. Asclepias viridis Walter (green-flowered milkweed, spider milkweed, Ozark milkweed)
Asclepiodora
viridis (Walter) A. Gray
Pl. 222 i, j;
Map 931
Plants with white
latex and a thickened, somewhat tuberous rootstock. Stems 20–60 cm long,
sometimes few-branched toward the tip, ascending to spreading, glabrous or
sparsely short-hairy toward the tip, with 12 to numerous nodes. Leaves mostly
alternate, sessile or short-petiolate. Leaf blades 2–12 cm long, 1–6 cm wide,
narrowly to broadly oblong, elliptic-lanceolate, or ovate, the base rounded,
narrowed, or less commonly shallowly cordate, the tip rounded or narrowed to a
blunt point, the margins flat, glabrous or sparsely and minutely hairy along
the midvein. Inflorescences 1–5, terminal and in the leaf axils, short-stalked,
with 3–20 flowers. Calyces spreading, glabrous or sparsely and minutely hairy
on the outer surface, the lobes 3–5 mm long, lanceolate to narrowly ovate.
Corollas ascending to spreading, glabrous, pale green to green, the lobes 10–17
mm long, elliptic-lanceolate to ovate. Gynostegium appearing sessile (the
corona base touching the corolla or nearly so), pale purple to purple, the
corona noticeably shorter than the tip of the anther/stigma head. Corona hoods
4–6 mm long, deflexed in the basal 1/3–1/2, with curved, ascending tips,
attached in the deflexed portion, the ascending portion narrowly club-shaped,
the tips hoodlike, the margins not toothed, the bases not pouched. Horns absent
(reduced to a small, platelike appendage near the tip of the inner surface of
the hoods). Fruits 6–13 cm long, erect or ascending from usually deflexed
stalks, broadly lanceolate to ovoid in outline, the surface smooth, glabrous or
more commonly minutely hairy. Seeds with the body 7–8 mm long, the margins
narrowly winged, the terminal tuft of hairs white to light cream-colored. May–June.
Scattered mostly
south of the Missouri River (southeastern U.S. west to Nebraska and Texas).
Upland prairies and glades, usually on calcareous substrates; also roadsides
and railroads.