DlOSCOREA. 



DIOSCOREACE.E. 



293 



1. Dioscorea villosa, Linn. Wild Yam-root. 



Herbaceous ; leaves mostly alternate, sometimes nearly opposite, or rarely in whorls of 4, 

 cordate, acuminate, entire, pubescent underneath, 9 - 1 1 -nerved ; fertile stamens 6. — Linn, 

 sp. 2. p. 1033 ; Pursh, fl. 1. p. 251 ; Bigel. fl. Bost. p. 368 ; Ell. sk. 2. p. 704 ; Torr. 

 compend. p. 374 ; Beck, hot. p. 355 ; Darlingt. fl. Cest. p. 567 ; Hook. ft. Bor.-Am. 2. 

 p. 207. D. paniculata, " Jacq. ic. t. 626 ;" Michx. fl. 2. p. 239. 



Rhizoma half an inch in diameter, horizontal, woody, somewhat knotted, with horizontal spurs. 

 Stem 6-10 feet long, slender, twining over bushes and other plants, smooth. Leaves 2-3 

 inches long, cordate or truncate at the base, conspicuously acuminate, marked with 9-11 strong 

 nerves which diverge from the base and curve towards the apex ; the two lateral ones confluent, 

 more or less pubescent and of a pale grayish color underneath. Flowers very small, pale 

 greenish yellow. Sterile fl. in pendulous panicles. Perianth deeply 5 - 6-parted ; the 

 segments ovate, sessile. Stamens much shorter than the perianth : filaments terete : anthers 

 introrse ; the cells roundish, distinct. Abortive ovary minute. Fertile fl. in pendulous simple 

 racemes. Segments of the perianth roundish, very short. Abortive stamens 6. Ovary 

 oblong, acutely triangular, 3-celled, with one or two pendulous anatropous ovules in each 

 cell. Styles very short, bifid. Capsule about three-fourths of an inch long, with 3 broad 

 semioval wings, which are of a dull yellowish green color, bordered with brown. Seeds one 

 or two in each cell, flatly lenticular, with a pale broad membranaceous margin. Embryo 

 somewhat pyriform, compressed, situated in a large thin cavity of the firm fleshy albumen, 

 near the hilum. 



Thickets, borders of woods, etc. Fl. June - July. Fr. October. 



Group 4. Flowers with a regular perianth, which is more or less petaloid (in Jun- 

 CACEiE, glumaceous) ; the segments often in a double series. Ovary free. 

 Embryo surrounded by albumem. — Herbs, rarely climbing or shrubby plants. 



Order CXVI. SMILACEiE. R. Brown. The Smilax Tribe. 



Flowers perfect or dioecious. Perianth petaloid, regular, 6-parted or 6-leaved 

 in a double series. Stamens G, hypogynous, or inserted into the perianth : 

 anthers mostly introrse, innate. Ovary free, 3- (or rarely 2-) celled, with one 

 - many ovules in each cell : the ovules either orthotropous, anatropous, or 

 hemitropous : styles 3, distinct to the base, or united into one. Fruit baccate. 

 Seed, with horny albumen. — Shrubs (usually climbing), or perennial herbs. 

 Leaves simple, mostly entire, often with reticulated veins. Flowers umbellate, 

 racemose or solitary, usually axillary ; the pedicels often jointed. 



