232 LEAFLETS. 



somewliere in Arizona in 1875, by Dr. lyoew. The two speci- 

 mens are on U. S. Herb, sheet 18,727. It was at first labelled 

 "a. erosa." That was afterwards (?) erased and "A. vestita " 

 substituted, this appellation also subsequently erased, all by 

 parties unknown. The small size of the plants, and peculiarly 

 small and dense foliage, preclude our referring it to either of 

 those species, not to speak of the flowers, the hoods of which, 

 while too short by half for those of A. erosa, have the pattern 

 of those of that species in all but their great brevity. In this 

 one particular only do they at first glance suggest A. vestita; 

 in structure, and as to the horn, they are far from it. 



AscLEPiAs RoTHROCKii. Allied to A. erosa, half as large, 

 more slender, canescently tomentulose : leaves oblong-oval, 

 2J^ to 4 inches long, subsessile, cordate at base, at apex 

 abruptly and cuspidately acute : umbels subsessile, their pe- 

 duncles barely yi inch long : hoods of the flower white, shorter 

 than the anthers, as broad as high, truncate and subcampanu- 

 late, the broadly lunate process much exserted, not very acute, 

 not horizontal over the anthers, but ascending. 



Collected by J. T. Rothrock, on Wheeler's Expedition of 

 1875, apparently at Fort Tejon, southern California. The 

 foliage has neither the size nor the form of that of T. erosa 

 from the same region. It is of thinner texture, also. That 

 of T. erosa, even from southern California, is almost coriaceous, 

 the leaf ovate in outline, modified by a long acuminate apex, 

 and the breadth of the leaf is greater than the greatest length 

 of that of T. RothrocMi. 



AscLEPiAS OBTUSATA. Of the size of A. erosa, but with 

 soft-hoary and thin flaccid foliage ; leaf outline elongate-oval, 

 short-petioled and not cordate at base, the apex in all but the 

 floral leaves very obtuse, even subtruncate, but always with a 

 small mucronation, length of leaf ZV^ inches, the breadth 2 

 inches, the texture quite thin : hoods exactly truncate, about 

 equalling the anthers, their process with a long point hori- 

 zontally extended. 



