428 Vail : Studies in the Asclepiad.aceae 



The type of this species is from lUinois, where it is not infre- 

 quently met with on river-banks and in thickets. It has a wide 

 range, eastward and southward. The specimen quoted from 

 Washington, D. C, as Vincetoxiciun gonocarpos laevism. Britton & 

 Brown, Ilkistrated Flora, 3: 18, is in fruit and is the true Gonolo- 

 bus lacvis Michx. (Herb. Columbia University). 



A second species Gonolobus volubilis {Nematiiris vohibilis 

 Turcz. Bull. Soc. Nat. Imp. Mosc. 21 : 254. 1848. Enslciiia 

 volubilis Karst. Fl. Columb. 2: 117. PI. 162. 1866) occurs 

 near Pt. Cabello, U. S. of Colombia. 



ViNCETOXicuM SUBEROSUM (L.) BHtt., Mem. Torn Bot. Club, 5: 



266. 1894. 



Cynanchiuii sitberosiim L. Sp. PI. 212. 1753. Dill. Hort. Elth. 

 300. pi. 22g. f. 2g6, excluding Hort. Cliff, and Gron. 27. 



Gonolobus suberosus R. Br. Ait. Hort. Kew. ed. 2, 82. 18 11. 



Dr. Gray * has written the history of this species and in addition 

 to his notes it may be of interest to point out that the plant 

 " Apocynuiji scandens fruticosiun fungoso corticc Brasiliamimy 

 Herm. Parad. 53 is probably the plant since referred to Ibatia, and 

 is not the specimen of the Hortus Cliffortianus which resembles it 

 only as to the corky, ridged bark of the stems. The Cliffort plant 

 can be seen in the Herbarium of the British Museum and is diffi- 

 cult to identify as it is a mere fragment, but the character of the 

 stem should make it easily recognizable were there more available 

 material of the same species for comparison. 



I venture to describe the following species as new. 



Vincetoxicum Floridanum. 



Puberulent throughout. Stems very slender, hirsute with few 

 short, scattered hairs : leaves opposite ; petioles 5-20 mm. long, 

 angled ; blades ovate, 2-5 cm. long, cordate, tapering to the acumi- 

 nate apex, the basal lobes rounded, with open sinus, about equally 

 puberulent with a fine soft pubescence on both surfaces; midvein ob- 

 scurely bi-glandulose at the base above : racemes about the length 

 of the petioles ; pedicels 1 2 mm. long : calyx very small ; seg- 

 ments 2 mm. long, linear-lanceolate, with a subulate gland in each 

 sinus: corolla dull greenish-purple, 5 -parted to a little below the 



* Proc. Am. Acad. 12: 75. 1876. 



