ASCLEPIADACEAE (MILKWEED FAMILY) 665 



the slender needle-pointed horn. — Swamps, N. B., westw. and southw. July, 

 Aug. 



Var. piilchra (Ehrh.) Pers. Leaves broader and shorter-petloled, more 

 or less hairy, as well as the stem ; flowers paler. (_A. pulchra Ehrh.)— N. S. 

 to N. C. and Ga., rarely w. to Minn. 



* * * Flowers greenish, yellowish, white, or merely purplish-tinged ; leaves oppo- 

 site or whorled, or the upper rarely scattered. 



*- Follicles echinate with soft spinous processes, densely tomentose (smooth, and 

 only minutely echinate at the apex in no. 8), large (8-13 cm. long), ovoid 

 and acuminate, erect on deflexed pedicels; leaves large and broad, short- 

 petioled ; umbels terminal and lateral. 



6. A. specibsa Terr, finely canescent-tomentose or glabrate, the many- 

 flowered umbel and calyx densely tomentose ; leaves subcordate-oval to oblong; 

 corolla-lobes purplish, ovate-oblong, 1 cm. long ; hoods slightly longer, with a 

 short inflexed horn, the truncate summit abruptly produced into a very long 

 lanceolate-ligulate appendage. — Along streams, Minn, to Ark., and westw. 

 June-Aug. 



7. A. syriaca L. (Common M. or Silkweed.) Stem tall and stout, finely 

 soft-pubescent ; leaves lance-oblong to broadly oval, 1-2 dm. long, pale, minutely 

 doivny beneath, as well as the peduncles, etc. ; corolla-lobes dull purple to white, 

 6-9 mm. long ; hoods rather longer than the anthers, ovate, obtuse, with a tooth 

 each side of the short stout claw-like horn. (A. Gornuti Dene.) — Rich ground, 

 N. B. to Sask., and southw. June-Aug. — Intermediates, perhaps of hybrid 

 origin, occur between this and some of the related species. 



8. A. Sullivintli Engelm. Vei-y smooth throughout, tall ; leaves ovate- 

 oblong with a somewhat heart-shaped base, nearly sessile ; hoods obovate, 

 entire, obtusely 2-eared at the base outside ; flowers larger (1.5-2 cm. long) and 

 more purple than in the preceding ; anther-wings 2-toothed at base ; pod nearly 

 glabrous, obscurely spiny chiefly on the beak. — Rich ground, s. Ont. and O. 

 to Kan., Neb., and Minn. June, July. 



-1- M- Follicles wholly unarmed, either glabrous or tomentulose-pubescent. 



** Follicles erect or ascending on the deflexed or decurved fruiting pedicels. 



= Umbel solitary, on a naked terminal peduncle; leaves sessile, broad, trans- 

 versely veined, wavy ; glabrous and pale or glaucous. 



9. A. amplexicaiilis Sm. Stem 3-8 dm. high ; leaves oblong, with a heart- 

 shaped clasping base, very obtuse or retuse, 4-12 cm. long ; peduncle 3-20 cm. 

 long ; corolla pale greenish-purple ; hoods truncate, somewhat toothed at the 

 summit, shorter than the slender awl-pointed horn. (A. obtusifolia Michx.) — 

 Sandy woods and fields, N. H. to Neb., and southw. June, July. — A second 

 umbel at the base of the peduncle occasionally occurs. 



10. A. Meadii Torr. Stem slender, 4-6 dm. high ; leaves ovate or oblong- 

 ovate, obtuse or acutish, 3-7 cm. long; peduncle only twice the length of the 

 upper leaves ; pedicels rather short ; corolla greenish-white ; hoods rounded- 

 truncate at summit, and with a sharp tooth at each margin, somewhat exceeding 

 the stouter horn. — Dry ground, Wise, 111., and la. June. 



= = Umbels mostly more than one ; peduncle not overtopping the leaves. 



a. Leaves large, orbicular to oblong-lanceolate; hoods broad, little if at all 

 exceeding the anthers ; glabrous or with some minute pubescence on young parts. 



11. A. phytolaccoJdes Pursh. (Poke M.) Stem 5-15 dm. high ; leaves 

 broadly ovate, or the upper oval-lanceolate and pointed at both ends, short- 

 petioled, smooth or slightly downy underneath, 1-3 dm. long ; lateral umbels 

 several ; pedicels loose and nodding, numerous, slender, 2-5 cm. long, equaling 

 the peduncle ; corolla-lobes ovate-oblong, greenish; hoods (white) truncate, the 

 margins 2-toothed at the summit, the horn with a long projecting awl-shaped 

 point. {A. exaltata Muhl. ? nomen subnudum.) — Moist copses, N..E. to Minn . 

 8. to Ga. and Ark, June-Aug. 



