ASCLEPIADACE^E. (MILKWEED FAMILY.) 239 



cially at the broader and strongly angulate upper portion: pollinia pear- 

 shaped, short-caudicled. — Proc. Am. Acad. xii. 66. Acetates decumbens, 

 Decaisne. From Utah through S. Colorado and New Mexico to Texas and 

 Arkansas. 



2. AS CLE PI AS, L. Milkweed. Silkweed. 



Herbs, from deep and thickish perennial roots : flowers umbellate ; the 

 peduncles terminal and lateral, usually between the petioles: follicles aoft- 

 echinate, warty or naked. 



§ 1 . Hoods sessile, not attenuate at base ; the horn or crest conspicuous : anther- 

 wings broadest and usually angulate-truncate and salient at base. 



* Corolla and hoods orange-color : follicles naked, erect on a deflexed pedicel: 



leaves mostly irregularly alternate, seldom opposite: juice of stem not milky. 



1. A. tuberosa, L. Hirsute or roughish-pubescent, 1 or 2 feet high, 

 very leafy to the top : leaves from lanceolate-oblong to linear-lanceolate, ses- 

 sile or slightly petioled : umbels several and mostly cymose at the summit of 

 the stem : hoods narrowly oblong, erect, deep bright orange, much surpassing 

 the anthers, almost as long as the purplish- or slightly greenish-orange oblong 

 corolla lobes, nearly equalled by the filiform-subulate horn : follicles cinereous- 

 pubescent. — From S. Colorado and Arizona to Texas, thence eastward to 

 Florida and Canada. Known commonly as " Butterfly-weed " or " Pleurisy- 

 root." 



* * Corolla and crown greenish, yellowish, white, or merely purplish-tinged : leaves 



opposite or sometimes whorled, or the upper rarely alternate or scattered. 

 +- Follicles echinate with soft spinous processes and densely tomentose, large (3 to 

 5 inches long) and ventricose, erect on deflexed pedicels: leaves large and broad, 

 short-petioled, transversely veined: stems stout and simple, 2 to 5 feet high. 



2. A. speciosa, Torr. Finely canescent-tomentose : leaves from sub- 

 cordate-oval to oblong, thickish : pedicels of the many-flowered dense umbel 

 and the calyx densely tomentose : flowers purplish, large : corolla-lobes 

 ovate-oblong : hoods spreading, the dilated body aud its short inflexed horn 

 not surpassing the anthers, but the centre of its truncate summit abruptly 

 produced into a lauceolate-ligulate thrice longer termination: column hardly 

 any : wings of the anthers notched and obscurely corniculate at base. — 

 Ann. Lye. N. Y. ii. 218. From Nebraska and Arkansas westward across the 

 continent. 



•«- •«- Follicles wholly unarmed and smooth throughout, either glabrous or 



tomentulose-pubescent. 



++ Erect or ascending on deflexed or decurved pedicels. 



= Umbel solitary on the perfectly simple strict stem, elevated on a naked terminal 



peduncle : leaves all closely sessile, broad, transversely veined. 



3. A. obtusifolia, Michx. Glabrous and pale or glaucous, 2 or 3 feet 

 high : leaves undulate, oblong or elliptical, 3 to 5 inches long, with rounded 

 or retuse apex and cordate-clasping base : peduncle 2 to 12 inches long: 



