188 BOTANY. 



Water-hole near Tucson, Ariz., Rothrock, 1874 (700). From Western 

 Texas to ►Southern California and into Mexico. 



Asclepiodora* decumbests, Gray, Proc. Amer. Acad. 12, 66. {Anan- 

 therix decumbens, Nutt; Acerates decumbens, Decaisne, Watson, Bot. King.)— 

 Santa Fe, N. Mex. (283), Rothrock, 1874. From Arkansas to Texas, New 

 Mexico, and Utah. 



Asclepias tuberosa, L. — Willow Spring, Arizona (200), Rothrock, 

 1874. Exactly like the common form of the States. Perhaps the most 

 western locality of this beautiful species. 



Asclepias speciosa, Torr. Ann. Lye. N. Y. 2, 218; Watson, I. c. 

 282.— Willow Spring, Arizona (249), Rothrock, 1874. 



Asclepias involucrata, Engelm. Bot, Mex. Bound. 163; Gray, Syn. 

 94. — Minutely pubescent when young, at last glabrate; several weak, 

 spreading stems from a stout root less than a span long ; leaves opposite or 

 alternate, lanceolate-linear, tapering, on short petioles, the broader ones with 

 a roundish, the others with a tapering base, the uppermost involucrating 

 the mostly solitary, sessile, or short-peduncled umbel, and commonly over- 

 topping it ; flowers greenish with purple ; ovate hoods rather longer than 

 the anthers, the short incurved horn slightly exserted from about their 

 middle ; pods ovate, acuminate, smooth, pubescent.— Algodones, N. Mex. 

 (78), Rothrock, 1874 ; also in Arizona and adjacent Mexico. 



Asclepias verticillata, L., var. subverticillata, Gray, Proc. Am. 

 Acad. 12, 71 ; Syn. 97. — Taller and stouter than the usual form, with leaves 

 3-5' long, opposite or ternate ; peduncles alternate all along the stem, many 

 times longer than the pedicels ; flowers rather larger than those of the 

 ordinary form. — Algodones, N. Mex. (77), Rothrock, 1874. Very similar 

 to Fendler's No. 694 from the same region. It approaches nearer to A. 

 Mexicana than to any of our varieties, but is readily distinguished by the 

 scattered (not subterminal) umbels, the flat leaves, with slightly revolute 

 margins, etc The roots of all the forms of verticillata are fascicled, the 



* Asclepiodora, Gray, Pioc. Amer. Acad. 12, CG ; Syrops. £8. (Ananlherix, in part, Nutt. ; Acerates, 

 in part, Decaisne anil others.) — Corolla rotate spreading, afterwards closed ; hoods inserted over the 

 whole (.short) column, spreading and assurgent, sac-shaped, upward 2-celIed by a salient crest. Anther- 

 wings corneous, narrowed at base, argulate above the middle ; polliuia dependent.— Stout, low, peren- 

 uial herbs, with usually scattered leaves and largo greenish flowers in subterminal umbels. 



