This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Rough-puberulent; stems slender, simple or little branched, erect or ascending, 1°-3° high. Leaves mostly alternate, linear or rarely linear-lanceolate, acute or acuminate, short-petioled, 2'-8' long, 1 1/2"- 6" wide, commonly rough-cilio-late on the margins and midrib; umbels several or solitary, peduncled, usually many-flowered; peduncles 3 -15" long; pedicels slender, hirsute, 1/2 - 1' long; corolla greenish white, its segments narrowly oblong, about 2" long; column short but distinct; hoods oblong, obtuse, entire, shorter than the anthers; anther-wings narrowed to the base; follicles densely puberulent, 4'-5' long.
Moist soil, Ohio to southern Ontario and Minnesota, North Carolina, Florida and Texas. June-Sept.
Acerates auriculata Engelm. Bot. Mex. Bound.
Sury. 160. 1859. Asclepias auriculata Holzinger, Bot. Gaz. 17:
Stem glabrous, often glaucous, sinuous above, rarely branched below, usually stout, 1°-3° high. Leaves mostly alternate, narrowly linear, glabrous, short-petioled, 3'-8' long, 1/2"-21/2" wide, becoming leathery, the rough margins not revolute; umbels commonly several, densely many-flowered, pedr.ncled; peduncles 2"-1' long, pubescent; pedicels slender, pubescent; flowers greenish white tinged with dull purple; corolla-segments oblong, 2"-2 1/2" long; column short, but distinct; hoods yellow, often with a purplish keel, entire, or emargi-nately truncate at the apex, not exceeding the anthers, the involute margins spreading at the base into auricles; follicles 2-3' long, curved.
In dry soil, Nebraska and Colorado to Texas and New Mexico. June-Sept.
Asclepias lanuginosa Nutt. Gen. 1: 168. 1818.
Hirsute all over; stems erect, slender, simple, 6'-18' high. Leaves oblong, ovate-lanceolate or lanceolate, obtuse at the apex, narrowed or rounded at the base, short-petioled, 1-4' long, 4"-15" wide; umbel solitary, terminal, densely many-flowered, peduncled; peduncle stout, densely hirsute, 1/2'-1 1/2' long; pedicels slender, puberulent or hirsute; corolla greenish, its segments oblong, about 2 1/2" long; column none; hoods purplish, oblong, obtuse, entire, with a flat fold or auricle on the infolded lower ventral margins, shorter than the anthers; anther-wings broadest below the middle.
On prairies, northern Illinois to Minnesota, Nebraska and Wyoming. June-Aug.