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..
A. Syriaca var. exaltata L. Sp. Pl. Ed. 2, 313. 1762.
Asclepias exaltata Muhl. Cat. 28. 1813.
A. phytolaccoides Pursh, Fl. Am. Sept. 180. 1814.
Nearly glabrous throughout, with two opposite lines of pubescence on the usually simple stem, 3°-6° high. Leaves opposite, thin or membranous, oval, ovate or oblong, acuminate at both ends, 4'-9' long, 1 1/2'-4' wide, the lower sometimes obovate, obtuse, shorter; petioles 1/4 - 1' long; peduncles l'- 3' long; umbels usually several; pedicels slender, drooping or spreading, 1' - 2' long, puberulent; corolla green-purple, the segments ovate or oblong, obtusish, 3"- 4" long; column short; hoods white or pink, slightly shorter than the anthers, much shorter than the subulate horn, at the summit truncate and entire or erose, with 1 or 2 slender teeth on each of the inner margins; follicles erect on the deflexed pedicels, downy, long-acuminate, 4'- 6' long.
Asclepias variegata L. Sp. Pl. 217. 1753.
Stem glabrous below, pubescent above when young, simple, 1° - 3° high. Leaves opposite, thick, oval, ovate, oblong or the lower somewhat obovate, obtuse and cuspidate or acutish at the apex, narrowed or rounded at the base, dark green above, pale beneath, 3' - 6' long, 1' - 3' wide, the middle ones sometimes verticillate in 4's; petioles 3"- 12" long; umbels 1-4, terminal, or rarely 1 or 2 in the upper axils, densely many-flowered; peduncles 1'-2' long; pedicels 1/2' - 1 1/2' long, erect or ascending, usually densely puberulent; corolla-segments ovate or oval, about 3" long, white, or purple near the base; column very short and thick, purplish; hoods globose-obovoid, obtuse, spreading, longer than the anthers, about equalling the semi-lunate horizontally pointed horn; follicles downy, erect on the deflexed fruiting pedicels, 4' - 5' long.
In dry woods or thickets, Connecticut (?), southern New York to Illinois, Arkansas, Florida and Texas. June-July.
A. quadrifolia Jacq. Obs. Part 2. 8. pl. 33. 1767.
Stem slender, simple, 1°-2° high, usually leafless below. Leaves thin, sparingly pubescent on the veins beneath, ovate to lanceolate, 2'-6' long, 1/2' - 2 1/2' wide, acute or acuminate, narrowed or rounded at the base, or the lowest pair much smaller, obovate and obtuse, the upper and lower opposite, the middle ones usually verticillate in 4's; umbels 1-4, terminal, or rarely in the upper axils; peduncles slender, 1/2'-2 1/2' long; pedicels about I long; corolla pink or nearly white, its lobes lanceolate-oblong, 2"-3" long; column short; hoods white, obtuse at the apex, broadly 2-toothed above the base, twice as long as the anthers and the short incurved horn; follicles erect on the erect fruiting pedicels, 3'-5' long, glabrous.
Woods and thickets, Maine and Ontario to Minnesota, Alabama and Arkansas. May-July.