STANDLEY TREES AND SHRUBS OF MEXICO. 1187 



Corolla lobes mostly oblong or lance-oblong, obtuse at the apex or 

 gradually attenuate, in bud only slightly overlapping. 



Corolla greenish 25. V. oaxacanum. 



Corolla brown-purple or blackish. 



Lobes of the outer corona lacerate-dentate 26. V. pilosum. 



Lobes of the outer corona crenulate or obscurely denticulate. 



Corolla lobes conspicuously veined 27. V. crenatum. 



Corolla lobes without conspicuous venation 28. V. grayanum. 



Corolla barbate or pilose within, at least in the throat. 



Corolla lobes oval or suborbicular, rounded, at apex 29. V. calcicola. 



Corolla lobes narrow or, if broad, acute or acuminate. 

 Leaves glabrous beneath or nearly so. 



Calyx about equaling the corolla. Leaves about as broad as 



long 30. V. cyclophyllum. 



Calyx much shorter than the corolla. 



Corolla lobes often barbate for their whole length with soft in- 

 terlaced hairs 31. V. barbatum. 



Corolla barbate only at the base with short stiff hairs. 



32. V. pectinatum. 

 Leaves pilose or hirtellous beneath, usually densely so. 



Corolla lobes linear 33. V. angustilobum. 



Corolla lobes lance-oblong or broader. 



Corolla glabrous outside or nearly so 34. V. uniflorum. 



Corolla puberulent or hirtellous outside. 



Corolla 2 to 2.5 cm. long 35. V. erianthum. 



Corolla 1 cm. long or less. 



Peduncles much longer than the petioles, long-hirsute. 



36. V. nigrescens. 

 Peduncles mostly shorter than the petioles, puberulent or 

 hirtellous. 

 Stems short-pilose or puberulent ; leaves broadest near the 

 base. 



Corolla 1.5 to 2 cm. broad 37. V. nemorosum. 



Corolla 6 to S mm. broad 38. V. jaliscense» 



Stems long-hirsute ; leaves broadest above the middle. 



39. V. xanthotrichum. 



1. Vincetoxicum hastulatum (A. Gray) Heller, Muhlenbergia 1: 2. 1900. 

 Lachnostoma hastulatum A. Gray Proc. Amer. Acad. 11: 87. 1876. 

 Gonolobus hastulatus A. Gray, Proc. Amer. Acad. 12: 78. 1876. 



Baja California ; type from Tantillas Canyon. 



Stems slender, chiefly herbaceous, finely pubescent ; leaves hastate, slender- 

 petiolate, pubescent ; flowers mostly solitary, short-pedicellate, whitish ; corolla 

 lobes oblong-linear ; follicles fusiform, 5 to 6 cm. long, smooth or with few 

 short tubercles. 



2. Vincetoxicum^ saepimentorum T. S. Brandeg. Univ. Calif. Publ. Bot. 4: 



381. 1913. 



Type from Bafios del Carrizal, Veracruz. 



Stems glabrous or nearly so ; leaves ovate-cordate, 4 to 6 cm. long, acuminate^ 

 glabrous or nearly so ; inflorescence racemiform, equaling or longer than 

 the leaves ; corolla lobes oblong, obtuse. 



