[+] Flowers rather large; hoods about 3´´ long and exceeding the anthers; leaves transversely veined.
2. A. paupércula, Michx. Glabrous; stem slender (2–4° high); leaves elongated-lanceolate or linear (5–10´ long), tapering to both ends, slightly petioled, umbels 5–12-flowered; divisions of the red corolla narrowly oblong; the bright orange hoods broadly oblong, obtuse, much exceeding the incurved horn.—Wet pine-barrens on the coast, N. J. to Fla. and Tex.
3. A. rùbra, L. Glabrous; leaves ovate or lanceolate and tapering from a rounded or heart-shaped base to a very acute point, sessile or nearly so (2–6´ long, ½–2½´ wide), bright green; umbels many-flowered; divisions of the corolla and hoods oblong-lanceolate, purple-red; the horn long and slender, straightish.—Wet pine-barrens, etc., N. J. and Penn. to Fla., La., and Mo.
4. A. purpuráscens, L. (Purple M.) Stem rather slender (1–3° high); leaves elliptical or ovate-oblong, the upper taper-pointed, minutely velvety-downy underneath, smooth above, contracted at base into a short petiole; pedicels shorter than the peduncle, 3–4 times the length of the dark purple lanceolate-ovate divisions of the corolla; hoods oblong, abruptly narrowed above; the horn broadly scythe-shaped, with a narrow and abruptly inflexed horizontal point.—Dry ground, N. Eng. to Minn., Tenn., and southward.—Flowers 6´´ long.
[+][+] Flowers small; hoods 1´´ long, equalling the anthers; veins ascending.
5. A. incarnàta, L. (Swamp Milkweed.) Smooth, or nearly so, in the typical form, the stem with two downy lines above and on the branches of the peduncles (2–3° high), very leafy; leaves oblong-lanceolate, acute or pointed, obtuse or obscurely heart-shaped at base; flowers rose-purple; hoods scarcely equalling the slender needle-pointed horn.—Swamps, common.—Var. púlchra, Pers.; leaves broader and shorter-petioled, more or less hairy-pubescent, as well as the stem. Milky juice scanty.—With the smooth form.
[*][*][*] Flowers greenish, yellowish, white, or merely purplish-tinged; leaves opposite or whorled, or the upper rarely scattered.
[+] Follicles echinate with soft spinous processes, densely tomentose (smooth, and only minutely echinate at the apex in n. 8), large (3–5´ long), ovate and acuminate, erect on deflexed pedicels; leaves large and broad, short-petioled; umbels terminal and lateral.
6. A. speciòsa, Torr. Finely canescent-tomentose or glabrate, the many-flowered umbel and calyx densely tomentose; leaves subcordate-oval to oblong; corolla-lobes purplish, ovate-oblong, 4–5´´ long; hoods 5–6´´ long, with a short inflexed horn, the truncate summit abruptly produced into a very long lanceolate-ligulate appendage.—Along streams, Minn. to Ark., and westward.
7. A. Cornùti, Decaisne. (Common Milkweed or Silkweed.) Stem tall and stout, finely soft-pubescent; leaves oval-oblong (4–8´ long), pale, minutely downy beneath, as well as the peduncles, etc.; corolla-lobes dull purple to white, 3–4´´ long; hoods rather longer than the anthers, ovate, obtuse, with a tooth each side of the short stout claw-like horn.—Rich ground, everywhere.