ASCLEPIADACE^E. (MILKWEED FAMILY.) 239 



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

 shaped, short-caudicled. Proc. Am. Acad. xii. G6. Acerates decumbens, 

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

 Arkansas. 



2. A SOLE PI AS, L. MILKWEED. SILKWEED. 



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

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

 echiuate, 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 deftexed 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. 

 t Follicles echinate ivith soft spinous processes and densely tomentose, large (3 to 

 5 inches long) and ventricose, erect on dejlexed 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 and its short inflexed horn 

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

 produced into a lanceolate-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. 



H- Erect or ascending on dejlexed 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 : Cleaves undulate, oblong or elliptical, 3 to 5 inches long, with rounded 

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



