356 smilacete. 



DIOSCOREA. Linn.— Yam. 



(In honor of the celebrated Greek naturalist, Dioscorides.) 



Dioecious. Perianth 6-parted, Sterile Fl. Stamens 6, 



3 sometimes barren. Filaments subulate. Fertile Fl. Styles 



distinct nearly to the base. Capsule 3-celled, triangular ; the 



angles winged. Seeds membranaceously winged. 



1. D. villosa Linn. : leaves alternate, opposite and verticillate, cordate, 

 acuminate, pubescent beneath, 9 — ll-nerved; lateral nerves simple, D, 

 paniculata Mich. 



Woods. Can. to Car. May, June. %. — Stem climbing, sometimes 10 or 12 



feet long. Leaves mostly alternate, sometimes subopposite, rarely in whorls of 

 4. Flowers minute, pale greenish-yellow; the sterile ones in penduloxis pani- 

 cles ; fertile ones in pendulous simple racemes. Hairy Yam. 



2. D. quaternata Walt. : leaves verticillate in fours, or alternate, cordate, 

 acuminate, smooth on both sides, 7-nerved ; lateral nerves bifid. D.glauca 

 MuM. 



Old fields. Penn. to Car. July. %■. — Stem climbing. Leaves more tapering 

 at the summit than ii^the preceding, of which, however, it maybe only a 

 variety. Smooth Yam. 



Order CXXX. SMILACE^. — Sarsaparillas. 







Flowers perfect or dioecious. Perianth petaloid, 6- (rarely 4-) 

 parted or 6-leaved in a double series. Stamens 6, (rarely 4,) 

 inserted into the. perianth, rarely hypogynous. Ovary 3-celled; 

 styles 3, distinct or united. Fruit a roundish berry. Seeds 

 with horny albumen. — Herbaceous plants or under shrubs, 

 usually climbing. Leaves simple, mostly entire, reticulated. 



1. SMIL AX. Linn.— Green Brier. 



(Greek ff/i(Xo^, from cuiXn, a knife or scraper ; most of the species being armed 

 with prickles.) 



Dioecious. Perianth campanulate, spreading, of 6 leaves in 



a double series, somewhat petaloid. Sterile Fl. Stamens 



mostly 6. Filaments short. Fertile Fl. Style very short 



Stigmas 3, thick. Berry 3- (or by abortion 1 — 2-) celled. 



Seeds 1 — 3, globose. 



* Stem shrubby. 



1. /S". quadrangularis Willd.: prickly; stem 4-angled, unarmed above; 



leaves unarmed, ovate, subcordate, acute, 5-nerved. 



Dry woods. Penn. to Car. June, July. T^.—i^erry black. Pursh. 



Square-stalked Greenbrier. 



2. )S. spinulosa Smith : stem terete, very prickly, with slightly recurved 



