ASCLEPIADACE^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. JE. albida, 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. nigrum, Mcench. (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-umbclled greenish or dark purple flowers, on pe- 

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

 and \o(36s, a pod, from the angled or ribbed follicles of some species.) 



1. G. l§evis, Michx. Nearly glabrous, or the stems and petioles sparingly 

 hirsute and finely puberulent; calyx and corolla ylabrous, 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. tiliaefo- 

 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. Sf 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. (Apocynumhirsutum, Pluk. ; perhaps Periploca 

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

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

 from the last by its short-ovate Jlower-buds. and the oval or oblong divisions of the 

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



