A-SCLEPIADACE^E. (MILKWEED FAMILY.) 355 



3. ENSL.feNIA, Nutt. ENSLENIA. 



Calyx 5-partcd. Corolla 5-parted ; the divisions erect, ovate-lanceolate. 

 Crown of 5 free raembranaceous leaflets, which are truncate or obscurely lobcd 

 at the apex, where they bear a pair of nexuous awns united at their base. An- 

 thers nearly as in Asclepias : pollen-masses oblong, obtuse at both ends, fixed 

 below the summit of the stigma to the descending glands. Pods oblong-lanceo- 

 late, smooth. Seeds with a tuft, as in Asclepias. A perennial twining herb, 

 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. allmla, Nutt. River-banks, Ohio to Illinois, W. Virginia, and 

 Bouthwestward ; common. July -Sept. Climbing 8 -12 high: leaves 3'- 

 5' wide. 



4. OONOL.OBUS, 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, more or less ribbed, or armed with soft warty projections. Seeds with 

 a silky tuft. Twining herbaceous or shrubby plants, with opposite heart-shaped 

 leaves, usually hairy, and racemed or corymbed greenish yellow or dingy purple 

 flowers, on peduncles rising from between the petioles. (Name composed of 

 y&vos, an angle, and Xo/3off, a pod, from the angled or ribbed follicles of one 

 species.) 



1. O. lliacropkyllllS, Michx. Stems and petioles somewhat pubes- 

 cent and hairy ; leaves round-cordate, large, very abruptly pointed ; lobes of the 

 corolla narrow ; pods ribbed-anyled. River-banks, Penn. 1 to Kentucky, and 

 southward. (The limits between this and G. tiliajfolius, Decaisne, appear un- 

 satisfactory.) 



2. O. tnirsiltllS, Michx. Stems and petioles bristly-hairy ; leaves round- 

 cordate or ovate-cordate, more or less hairy ; lobes of the corolla oblong pod* 

 armed with soft prickles. River-banks, Penn. to S. Illinois, and southward. 

 July. 



5. PERIPL.OCA, L. PERIPLOCA. 



Calyx 5-parted. Corolla 5-parted, wheel-shaped, with 5 awned scales b the 

 throat. Filaments distinct : anthers coherent with the apex of the stigma, 

 bearded on the back : pollen-masses 5, each of 4 united, singly affixed directly 

 to the glands of the stigma. Stigma hemispherical. Pods smooth, widely di- 

 vergent. Seeds with a silky tuft. Twining shrubby plants, with smooth oppo- 

 site leaves, and pan icled-cymose flowers. (Name from Tre/KTrXo/t^, a coiling 

 round, in allusion to the twining steins.) 



1. P GR^CA, L. Leaves ovate or ovate-lanceolate, shorter than the loose- 



