YAM FAMILY. 447 
1. DIOSCOREA L,. Sp. Pl. 1032. 1753. 
Characters of the family as defined above. [Name in honor of the Greek naturalist 
Dioscorides. ] 
There are about 160 species, most numerous in tropical regions, a few extending into the tem- 
perate zones. The large fleshy rootstocks of several tropical species furnish the yams of commerce. 
1. Dioscorea vill6sa L. Wild Yam-root. (Fig. 1068.) 
Dioscorea villosa V,. Sp. Pl. 1033. 1753- - ¢ Yy 
Rootstock knotted, horizontal, woody, '%/-1’ Vi f..” 
thick. Stem 6°-15° long, twining or rarely sub- ie 
erect, glabrous; leaves ovate, entire, slender- 
petioled, alternate or the lower opposite or in 4’s, 
acuminate at the apex, cordate at the base, 2/-6/ 
long, 1/-4’ wide, 9-13-nerved, thin, green and 
glabrous or nearly so aboye, pale and more or 
less pubescent beneath; petioles often longer than 
the blades; flowers greenish yellow, nearly ses- 
sile, the staminate 1//-1's’’ broad in drooping 
panicles 3’—6’ long, the pistillate about 3’” long in 
drooping spicate racemes; capsules membranous, 
yellowish green, 7’/-12’’ long, strongly 3-winged, 
containing 2 or sometimes only 1 flat thin-winged 
seed in each cavity. ; 
In moist thickets, Rhode Island to Ontario and Min- 
nesota, south to Florida and Texas. Ascends to 4000 
ft. in Virginia. June-July. Fruit ripe Sept., per- 
sistent on the vines into the winter. 
Family 25. IRIDACEAE Lindl. Nat. Syst. Ed. 2, 382. 1836. 
IrIs FAMILY. 
Perennial herbs with narrow equitant 2-ranked leaves and perfect regular or 
irregular mostly clustered flowers subtended by bracts. Perianth of 6 segments 
or 6-lobed, its tube adnate to the ovary, the segments or lobes in two series, 
convolute in the bud, withering-persistent. Stamens 3, inserted on the perianth 
opposite its outer series of segments or lobes; filaments filiform, distinct or 
united; anthers 2-celled, extrorse. Ovary inferior, mostly 3-celled; ovules 
mostly numerous in each cell, anatropous; style 3-cleft, its branches sometimes 
divided. Capsule 3-celled, loculicidally dehiscent, 3-angled or 3-lobed (some- 
times 6-lobed), many-seeded. Endosperm of the seed fleshy or horny; embryo 
straight, small. 
About 57 genera and 1000 species, of wide distribution. 
Style-branches opposite the anthers, very broad, petal-like. ep LADS. 
Style-branches alternate with the anthers, slender or filiform. 
Style-branches 2-cleft; plants bulbous. 2, Nemastylis. 
Style-branches undivided; plants not bulbous. 
Filaments all distinct; seeds fleshy. 
Filaments united; seeds dry. 
. Gemmingta. 
. Stsyrinchium, 
Sw 
TE TRIS: Speblnsss 1753: 
Herbs with creeping or horizontal, often woody and sometimes tuber-bearing rootstocks, 
erect stems, erect or ascending equitant leaves, and large regular terminal sometimes pan- 
icled flowers. Perianth of 6 clawed segments united below into a tube, the 3 outer dilated, 
spreading or reflexed, the 3 inner narrower, smaller, usually erect, or in some species about 
as large as the outer. Stamens inserted at the base of the outer perianth-segments; anthers 
linear or oblong. Ovary 3-celled; divisions of the style petal-like, arching over the stamens, 
bearing the stigmas immedfately under their mostly 2-lobed tips; style-base adnate to the 
perianth-tube. Capsule oblong or oval, 3-6-angled or lobed, mostly coriaceous. Seeds nu- 
merous, vertically compressed in 1 or 2 rows in each cell. [Greek, rainbow, referring to the 
variegated flowers. ] 
About 100 species, mostly in the north temperate zone. Besides the following, some 8 others 
occur in the southern and western parts of North America. The names Flower-de-luce and /leur- 
de-lis are applied to the species. 
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