ASCLEPIADACEAE 953 



Crown prominently toothed; crest a narrow ridge or fold that 



is barely free within. 5. V. Shortii. 



Crown merely crenulate, crest double. G. 1'. obliquum. 



Alternate divisions of the crown distinctly 2-toothed, thinner and 

 narrower than the rounded somewhat crenate divisions that 

 are more or less obscurely crested within : crests entire, crenate 

 or bitid. " 7. 1'. CaroUnense. 



(orolla dull reddish, in the variety greenish yellow or straw-colored. 8. 1'. hirsutum. 



b. Corolla white : crown-divisions broad, quadrate, alternating with 5 slen- 

 der deeply 2-toothed segments that much surpass the anthers. 9. V. Baldwinianum. 

 Pollinia oblong : crown .S-crenate. the divisions each 4-toothed : flowers in 



short racemes or fascicles. 10. T'. Flondanum. 



B. Stems low, procumbent or diffuse, in V. productum twining : leaves small. 

 Flowers solitary or 2, rarely 3 in a fascicle, never long-peduncled. 

 Corolla rotately spreading. 



Crown 5-undulate, each lobe with an obtuse or subquadi-ate inflexed 

 adnate crest, the intermediate sinus fringe-toothed : follicles muri- 

 cate and hirsute. 11. V. biflorum. 



Crown .>parted : lobes broadly refuse, appendaged within by a thick 



fleshy ligule : follicles large and thick, muricate. 12. V. cynanchoides. 



Corolla campanulate. 



Crown 5-parted or apparently 10-parted, each alternate division with 

 an incurved beak terminating the adnate crest within : follicles 

 muricate. 13. V. pubiflorum. 



Crown saucer-shaped, with .5 internal, barely free processes terminat- 

 ing the adnate crests within : follicles sinooth : stem twining. 14. }'. productum. 

 Flowers several in a slender long-peduncled raceme : corolla rotate, small. 

 Crown-lobes deeply 2-toothed, each with a slender, much longer, erect or 



incurved process within. 15. T'. parviflorum. 



Crown-lobes emarginate or truncate, each with a slender, erect process 



within. 16. T'. brevicoronatum. 



1. Vincetoxicum reticulatuni (Engelni. ) Heller. Stems high-climbing, hirsute 

 with long stiff spreading hairs and a minute glandular pubescence : leaf-blades ovate- 

 oblong, deeply cordate with incurved rounded and often overlapping auricles, tapering to 

 a long-acuminate apex, 5-10 cm. long, glabrate or sparingly pubescent above, minutely 

 puberulent and granulose beneath : peduncles as long as the petioles (2-10 cm. ) or longer : 

 cymes o-lO-Howered : calyx with a gland at each sinus : corolla dull purplish green, 

 1.4 cm. broad ; lobes oval, obtuse, scarious-raargined, minutely and sparingly papillose or 

 pubescent outside, green and white-reticulated within : crown an obscure ring attached to 

 the base of the corolla : column slender, 1 nun. high, 5-angled, with a fleshy, rather obscure, 

 angled ring approximated above that of the crown : stigma obtusely 5-angled, obscurel}' 

 conic : pollinia pyriform : ovaries glabrate : follicles 8-12 cm. long, fusiform, long-acu- 

 minate, glabrate or minutely puberulous, strongly muricate : seeds 7 mm. long, minutely 

 granulose : coma 3.5 cm. long. 



In thickets and on rocky banks, Texas to Arizona and Mexico. Spring to fall. 



2. Vincetoxicum Alabatneuse Vail. Stems high-climbing, sparingly hirsute with 

 long rather weak hairs and a minute glandular pubescence : leaf-blades 6-15 cm. long, 

 5-10 cm. broad, rather thin, ovate or oblong-cordate, acuminate at the apex, the basal auri- 

 cles rounded and never overlapping, the sinus narrowed at the base, sparingly puberulent 

 and dark green above, lighter and more closely puberulent beneath : peduncles shorter 

 than the petioles : cymes 3-6-flowered : calyx biglandulose ; lobes lanceolate, acute : co- 

 rolla dull greenish yellow, 2 cm. in diameter ; lobes oval, obtuse, puberulent, and minutely 

 papillose, on the outer surface, conspicuously reticulated within : gynostegium raised 

 on a low broad column : crown orange-yellow, consisting of a low saucer-shaped ring at- 

 tached to the base of the corolla, 5-parted, each division minutely and irregularly toothed 

 or entire, appendaged within by 5 tooth-like erect crests attached to the base of the column : 

 stigma white, flat, obtusely 5-angled : anther-tips white, scarious : pollinia pyriform : ovaries 

 minutely puberulent : follicles 8-9 cm, long, glandular-puberulent, closely and strongly 

 muricate : seeds 8-9 mm. long, obovate, granulose : coma 3.5-4.5 cm. long. 



In thickets and on sandy hillsides. Dale County, Alabama. Summer and fall. 



3. Vincetoxicum suberosum (L. ) Britton. Stems slender, twining, pubescent or 

 glabrate, often with few scattered and spreading hairs : leaf-blades ovate-oblong or the 

 smaller ones oblong-oval, thickish, 6-12 cm. long, 2.5-8 cm. wide, abruptly acuminate at the 

 apex, sometimes a little contracted at the middle, cordate or subcordate at the base, the 

 sinus sliallow, rather wide and open, the basal lobes rounded : racemes few-several- 

 flowered : peduncles shorter than the pedicels, which are 1-2.5 cm. long, stout and fleshy : 

 calyx with a subulate gland in each sinus : corolla brown-purple or some of them yellowish, 

 broadly conic in the bud ; lobes lanceolate or ovate-lanceolate, acute, pubescent or granu- 

 lose within, 7-8 mm. long, erect or rotately spreading : crown an annular disk, undulatel}' 

 5- or barely 10-crenate, adnate to tlie corolla and but oltscurely connected with the very 

 short column by 5 faint ascending ridges : stigma depressed, barely 5-rayed : pollinia pyri- 

 form, rounded at the base, with broad winged caudicles : follicles 10-12 cm. long, 2.5-8 



