A S CL EPIA D A CEA E. 743 



10-15 cm - l° n g- ^ n dry fields, mostly in sandy soil, Me. to Fla., Minn., Kans. and 

 Tex. May— Aug. [--/. obtusifolia Michx.] 



11. Asclepias Meadii Torr. Mead's Milkweed. (I. F. f. 2910.) Nearly 

 glabrous throughout, pale green or glaucous; stem simple, or rarely branched 

 above, 3-6 dm. high. Leaves flat, mostly distant, ovate, ovate-lanceolate, lanceo- 

 late or the lower oblong, the margins scabrous; umbel several-flowered, borne on a 

 peduncle 8-15 cm. long; corolla-segments greenish yellow, ovate, acute, 6-9 mm. 

 long; hoods ovate, purplish, nearly twice as long as the anthers, rounded and 

 truncate at the summit, longer than the subulate inflexed horn, with a small tooth 

 at each side on the inner infolded margin; follicles erect on decurved pedicels, 

 puberulent, narrow, 10-12 cm. long. Dry soil, 111. to Iowa and Wise. June-Aug. 



12. Asclepias exaltata (L. ) Muhl. Poke or Tall Milkweed. (I. F. f. 

 291 1.) Nearly glabrous throughout, with two opposite lines of pubescence on the 

 usually simple stem, 1-2 m. high. Leaves thin or membranous, oval, ovate or 

 oblong, acuminate at both ends, 10-23 cm - long, 3-10 cm. wide, the lower some- 

 times obovate, obtuse, shorter; peduncles 2.5-8 cm. long; umbels usually several; 

 pedicels slender, drooping or spreading, 2.5-5 cm - l° n g> puberulent; corolla-seg- 

 ments ovate or oblong, obtusish, 6-9 mm. long; hoods white or pink, slightly 

 shorter than the anthers, much shorter than the subulate horn, at the summit 

 truncate and entire or erose, with I or 2 slender teeth on each of the inner mar- 

 gins; follicles erect on the deflexed pedicels, downy, long-acuminate, 10-15 cm * 

 long. In thickets and woods, Me. to Minn., Ga. and Mo. June-Aug. 



13. Asclepias variegata L. White Milkweed. (I. F. f. 2912.) Stem 

 glabrous below, pubescent above when young, simple, 3-9 dm. high. Leaves 

 thick, oval, ovate, oblong or the lower somewhat obovate, obtuse and cuspidate or 

 acutish. dark green above, pale beneath, 6-15 cm. long, the middle ones sometimes 

 verticillate in 4's; petioles 6-25 mm. long; umbels 1-4, terminal, or rarely I or 2 in 

 the upper axils, densely many-flowered; pedicels erect or ascending, usually 

 densely puberulent; corolla- segments ovate or oval, about 6 mm. long, white, or 

 purple near the base; column 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, 10-13 cm. long. In 

 dry woods and thickets. Conn, to 111., Fla., Ark. and La. June-July. 



14. Asclepias quadrifolia Jacq. Four-leaved Milkweed. (I. F. f. 2913.) 

 Stem slender, simple, 3-6 dm. high, usually leafless below. Leaves thin, spar- 

 ingly pubescent on the veins beneath, ovate to lanceolate, 5-15 cm. long, acute or 

 acuminate, or the lowest pair much smaller, obovate and obtuse; umbels 1-4, ter- 

 minal, or rarely in the upper axils; peduncles slender; corolla-lobes lanceolate- 

 oblong. 4-6 mm. long; hoods white, obtuse at the apex, broadly 2-toothed above ihe 

 base, twice as long as the anthers and the incurved horn; follicles erect on the 

 erect fruiting pedicels, 8-13 cm. long, glabrous. Woods and thickets, Me. and 

 Ont. to Minn.. N. Car. and Ark. May-July. 



15. Asclepias Syriaca L. Common Milkweed. Silkweed. (I. F. f. 

 2914.) Stem stout, usually simple. 9-15 din. high, finely pubescent at least above. 

 Leaves oblong, oval or ovate, densely pubescent beneath, soon glabrous above, IO- 

 23 cm. long, the primary nerves wide-spreading; petioles stout, 6-17 mm. long; 

 umbels several or numerous; peduncles pubescent or tomentose, 3-9 cm. long; 

 pedicels 2.5-5 cm. long; corolla green-purple, its segments oblong-lanceolate, 6-9 

 mm. long; hoods ovate-lanceolate with a tooth on each side, longer than the anthers 

 and the incurved horn; follicles 6- 13 cm. long, erect on recurved pedicels. In 

 fields and waste places, N. B. to the N. W. Terr., N. Car. and Kans. Leaves 

 rarely lanceolate. June-Aug. [A. Cornuti Dec] 



16 Asclepias speciosa Torr. Showy Milkweed. (I. F. f. 2915.) White- 

 tomentose or canescent all over, or glabrate below, pale; stem simple, stout, 3-7 

 dm. high. Leaves thick, broadly ovate or oval, petioled, 8-20 cm. long; pedun- 

 cles 2.5-7 cm. long; umbels several or rarely solitary, many-flowered; pedicels 

 stout; corolla purple-green, its segments oblong or ovate-oblong, 9-13 mm. long, 

 tomentose on the outer face: column very short or none; hoods lanceolate. 11-15 

 mm. long, obtusish, expanded and with 2 blunt teeth below, the apex ligulate, 5-7 

 times as long as the anthers; horn short, inflexed; follicles erect or spreading on 



