APOCYNACE^E. 17 



ASCLEPIAS HALLII, Gray. Excellent specimens of a plant 

 that is rare; obtained at Gunnison, 25 July, n. 595. 



APOCYNUM AMBIGENS. Intermediate between A. andro- 

 ssemifolium of the East and A. pumilum of the Pacific slope; 

 smaller than the former, more erect and 'more copiously 

 floriferous, the corollas larger but still campanulate; follicles 

 much shorter and thicker. 



In the Black Canon, 20 June, n. 202; also at Rogers', 14 

 Aug., n. 799. The plant is frequent in several parts of 

 Colorado, and has passed for A. androsaemifolium; but both 

 this and A. pumilum are better accepted as fair geographical 

 subspecies. 



APOCYNUM CANNABINUM, Linn. In moist ground on 

 Deer Run, 10 June, n. 80. 



APOCYNUM LIVIDUM. Several feet high, with the pale 

 and glaucescent hue of A. cannabinum, but the oblong- 

 ovate mucronate leaves much larger and more spreading-' 

 inflorescence consisting, as in that species, of terminal and 

 naked cymes, but flowers few, large and nodding, of a pale 

 flesh- color; sepals thin and whitish, triangular-lanceolate, 

 erect, half as long as the corolla, this campanulate, rather 

 deeply cleft and with spreading or recurved segments. 



Common on railway embankments in Black Canon, 8 

 July. The plant recalls the Californian A. floribundum, 

 but differs in having few and large flowers rather than 

 almost innumerable small ones. 



ASPERIFOLI^. 



MERTENSIA CONGESTA. Tufted stems a foot high or less, 

 stout and rather succulent, ascending; whole herbage of a 



