DIOSCOBEACEAE 319 



cent beneath, the upper ones sometimes nearly opposite, or in 



verticils of four. 



VILLOUS DIOSCOREA. Wild Yam. 



Stem 6 to 12 feet long, Blender, mostly simple, twining (W- S. E.), or clamber- 

 ing over bushes and fences. Leaves 2 to 4 inches long, 9- to IX-nerved ; petioles 1% 

 to 2^ inches in length. Capsules about % of an inch in length, and nearly as 

 wide as long, the angles dilated into 3 broad compressed semi-oval wings, which 

 are greenish-tawny, with a narrow dark-brown margin. Seeds orbicular, with a 

 thin white shining membranaceous margin. 

 Hab. Thickets ; fence-rows, &c.: frequent. Fl. June. Fr. Octo. 



Obs. I have observed, in the pistillate flowers, 6 abortive stamens, 

 or staminodia ; but do not know whether they are constant. The 

 fine tuberous rhizoma, known as the Yam, in tropical countries, is 

 afforded by a species of this genus (D. saliva, L.). 



ORDER CX. SMILACEAE. 



Herbs, or climbing shrubby plants ; leaves alternate, or verticillate, ribbed and netted- 

 reined, sometimes with tendrils in place of stipules ; flowers regular, dioicous, or 

 perfect, the perianth mostly 6-parted, free from the ovary ; stamens as many as 

 the perianlh-lobes ; anthers introrse; ovary 3- to 5-celled; styles or stigmas as 

 many, and distinct; fruit a few- or many-seeded berry; embryo minute, in hard 

 albumen. 



SUBORDER I. TRUE SMILAX3EAE. 



Chiefly shrubby; leaves alternate, cirrhose-stipulate ; flowers mostly dioicous, 

 axillary, the perianth uniform ; stigmas subsessile ; seeds few. 



434. SMIXAX, Tournef. 

 [The ancient Greek name; meaning obscure.] 



Perianth of 6 nearly distinct deciduous sepals. Stamens as many ; 

 anthers linear, fixed by the base. Stigmas 3, thick and spreading. 

 Berry globular, bluish-black, 1- to 3-celled, 1- to 3-seeded; seeds 

 globose. Perennials: often evergreen and prickly; climbing by 

 tendrils on the petioles ; flowers greenish-yellow, in axillary pedun- 

 culate simple umbels. 



1. Stem shrubby and prickly; leaves thicldsh; ovules solitary. 



1. S. rotundifdlia, L. Leaves roundish-ovate, with a short 

 acumination, subcordate at base, glaucous beneath. 

 ROUND-LEAVED SMILAX. Green-Brier. Rough Bind- weed. 



Plant yellowish-green, smooth (as to [pubescence). Stem 10 to 20 or 30 feet long, 

 mostly terete, flexuose, somewhat branched, armed with straight sharp prickles. 

 Leaves 2 to 8 inches long ; petioles % to % of an inch in length, margined at base, 

 and with a simple filiform but strong tendril, on each side, at the summit of the 

 margin. Umbels globose, on peduncles scarcely longer than the petioles. Berries 

 with a glaucous bloom. 



Far. Caduca, A. Gray. Stem somewhat angular, shorter and more slender, 

 seldom climbing ; leaves ovate, mucronate. 

 S. caduca. L. and Fl. Cettr. ed. 2. p. 506. 

 Hab. Thickets ; moist woods ; old fields : frequent. Fl. May, June. Fr. Octo. 



Obs. Prof. GRAY has reduced the S. caduca, L. to a variety. It 

 is chiefly found in old fields ; while the other occurs in wet woods, 



