ASCLEPIADACEiE. 403 



7. ACERATES, Ell. An extension of the generic character, as to the 

 hoods, is needed to include the following, which in other respects falls under the 

 second division, p. 99. 



A. bifida, Rusby. Generally resembling A. viridiflora, a foot, or two high, tomentose- 

 puberulent : leaves oblong-lanceolate, tapering into short petioles : pedicels rather slender : 

 hoods of the crown paler, rather shorter than the anthers, two-parted, the divisions lanceolate. 

 — Gray, Proc. Am. Acad. xx. 296. — Arizona, probably in Yavapai Co., Rusby, 1 883. 



9. G-OMPHOCARPUS, E. Br. 



G. tomentosUS, Gray, p. lOO. Hoods dark brown-purple, the solid part not much smaller 

 than the valves : the structure not to be confounded with that of Schizonotus,ioT the 2-valved 

 portion is only apparently dorsal, the whole organ being pendulous or resupinate. It ia 

 similar in G. lanatus of S. Africa, except that the hood is ascending. 



G. hypoleiicus, Geay. Tomentulose: stem robust, 2 feet high, leafy: leaves all opposite, 

 oval or oblong, short-petioled, green and glabrate above, canescently tomentose beneath : 

 umbels long-petioled, many-flowered : corolla greenish with the upper face dull purple : 

 hoods brown-purple, erect, much surpassing the anthers, Ungulate, fleshy, nearly solid and 

 entire, except a pair of triangular and acute strictly inflexed lobes at base. — Proc. Am. 

 Acad. xvii. 222. — Mountains of S. Arizona, Pnngle, Lemmon. 



12. METASTELMA, R. Br., § Eumetastelma. P. 101, add: — 



M. Palmeri, Watson. Glabrous : leaves lanceolate, acutish or obtuse at base, about an 

 inch long : cymes loosely 2-6-flowered, subsessile or short-peduncled : calyx-lobes ovate, ob- 

 tuse : corolla not over a line and a half long, 5-parted ; its lobes oblong or narrower, merely 

 puberulent within : scales of the crown lanceolate and acuminate or ovate-subulate, inserted 

 at base of extremely short column, a little surpassing the stigma. — Proc. Am. Acad, xviii. 

 115, as to pi. Palmer only; Gray, Rev. Metastelma in Proc. Am. Acad. xxi. — W. and S. 

 borders of Texas, Palmer, Reverchon. (Adj. Mex.) 



M. Arizonicum, Geay. Puberulent, lignescent at base : leaves thickish, narrowly linear 

 or some linear-oblong, veinless : flowers fascicled and short-pedicelled : calyx-lobes subulate : 

 corolla 2 lines long, thickish, deeply 5-parted ; lobes linear-lanceolate, densely villous- 

 pubescent inside ; scales of the crown linear-subulate, inserted at base of very short col- 

 umn, surpassing the stigma. — Proc. Am. Acad. xix. 85. — Hills near Tucson, Arizona, 

 Pringle. 



14. VINCETOXICUM, Mcench. (Derivation doubtless from vincere, to 

 overcome, toxicum, poison, as has been well shown.) 

 V. palustre, p. 102. Add. syn. : Cynanchum mantimum, Maxim, in Bull. Acad. Petrop. 



ix. 800. 

 V. SCOparium, p. 102. Leafy plants not rarely bear leaves an inch or two long, a line or 



two wide. 



14 1 . ROTHROCKIA, Gray. (Professor Joseph Trimble Rothrock, authoi 

 of the Botanical Part (vol.vi.) of Wheeler's U. S. Geographical Surveys of the 

 region in which the plant was discovered.) — Proc. Am. Acad. xx. 295. — Single 

 species. 



R. oordifolia, Geay, 1. c. Perennial herb, lignescent at base, spreading and twining, pu- 

 bescent and more or less hirsute : leaves opposite, slender-petioled, cordate, acutely acumi- 

 nate: flowers in simple or compound racemiform loose racemes in the axils of the leaves: 



