ASCLEFIADACE^E. (MILKWEED FAMILY.) 399 



smooth, with opposite heart-ovate and pointed long-petioled leaves, and small 

 whitish flowers in raceme-like clusters, on slender axillary peduncles. (Dedi- 

 cated to A. Enslen, an Austrian botanist who collected in the Southern United 

 States early in the present century.) 



1. E. alb i da, Nutt. River-banks, Ohio to Illinois, and southward : com- 

 mon. July - Sept. Climbing 8 - 12 high : leaves 3' - 5' wide. 



4. VINCETOXICUM, Mcench. VINCETOXICUM. 



Calyx 5-parted. Corolla 5-parted, wheel-shaped. Crown flat and fleshy, 

 disk-like, 5 - 10-lobed, simple. Anthers smooth, pods and seeds much as in 

 Asclepias. Herbs, often twining. (Name composed of Vinca, the Periwinkle, 

 and toxicum, poison.) 



1. V. KIGRUM, Mo3nch. ( BLACK V.) More or less twining, nearly smooth ; 

 leaves ovate or lance-ovate ; flowers small, dark purple, in an axillary cluster, 

 on a peduncle shorter than the leaves. Cambridge, Mass., &c. : a weed escap- 

 ing from gardens. (Adv. from Eu.) 



5. GONOLOBUS, Michx. GONOLOBUS. 



Calyx 5-parted. Corolla 5-parted, wheel-shaped, sometimes reflexed-spread- 

 ing ; the lobes convolute in the bud. Crown a small and fleshy wavy-lobed ring 

 in the throat of the corolla. Anthers horizontal, partly hidden under the flat- 

 tened stigma, opening transversely. Pollen-masses 5 pairs, horizontal. Pods 

 turgid, mostly muricate with soft warty projections, sometimes ribbed. Seeds 

 with a coma. Twining herbs or shrubs (ours herbaceous), with opposite heart- 

 shaped leaves, and corymbose-um belled greenish or dark purple flowers, on pe- 

 duncles rising from between the petioles. (Name composed of yavos, an angle, 

 and Xo/3os, a pod, from the angled or ribbed follicles of some species.) 



1 . G. Isevis, Michx. Nearly glabrous, or the stems and petioles sparingly 

 hirsute and finely puberulent ; calyx and corolla glabrous, the latter tapering-con- 

 ical in the bud, the expanded divisions lanceolate, yellowish-green ; pods ribbed, 

 smooth. ( Vincetoxicum gonocarpos, Walt. Periploca late-scandens, Clayt. G. 

 macrophyllus, Michx., also Decaisne, excl. syn. Jacq. & Bot. Mag. G. tilisefo- 

 lius, Decaisne. ) River-banks, Virginia, to Illinois and southward. July. 



2. G. Obliquus, R. Br. Stems, petioles and often the ribs of the leaves 

 beneath hirsute with spreading viscid hairs ; calyx and corolla pubescent or puberu- 

 lent outside, the latter narrow-conical-oblong in the bud, its divisions ligulate- 

 linear or lanceolate, obtuse, dark dull crimson-purple within ; pods copiously muri- 

 cate, ribless. (Cynanchum obliquum, Jacq., 1786. C. discolor, Sims, Bot. 

 Mag. Gonolobus hirsutus, Ed. 2, &c. G. discolor, R. fr S. G. macrophyllus, 

 Decaisne in part. ) River-banks, Penn. to Virginia. Aug., Sept. Lobes of 

 the corolla nearly 6" long. Pod 5' long. 



3. G. hirsutus, Michx. (Apdcynumhirsutum. Pluk. ; perhaps Periploca 

 Carolinensis, DHL, and P. late-scandens fl. ferrugineo, Clayt. ; Vincetoxicum 

 acanthocarpos, Walt. ; and clearly Cynanchum Carolinense, Jacq.) Known 

 from the last by its short-ovate flower-buds, and the oval or oblong divisions of the 

 purple corolla (only about 3" long) ; perhaps occurs in S. E. Virginia. 



