474 DIOSCOREACE^E. (YAM FAMILY.) 



1. S. Bermudiana, L. Leaves linear, erect; stem simple or sparingly 

 branched, naked or 1 - 2-leaved, more or less broadly 2-winged ; leaves of the 

 spathe equal and shorter than the flowers, or the lower one much longer than 

 the flowers ; perianth blue, yellow in the centre ; the divisions notched and 

 bristle-awned at the apex. (S. mucronatum, Michx.) Grassy meadows, or 

 sometimes in dry soil, Florida, and northward. July and Aug. Stem 6'- 18' 

 high. Leaves mostly shorter than the stem. Flowers 4 - 6 in a spathe, ' wide, 

 opening in the evening. 



3. NEMASTYLIS, Nutt. 



Perianth 6-parted, the divisions nearly equal and spreading. Stamens 3, dis- 

 tinct, with the subulate filaments much shorter than the elongated linear anthers. 

 Style short, 3-lobed, with the lobes 2-parted, each division produced into filiform 

 radiating stigmas. Capsule oblong, truncated. Herbs with coated bulbous 

 roots, linear plicate leaves, and very fugacious flowers from a 2-leaved spathe. 



1. N". coelestina, Nutt. Bulb small, roundish; radical leaves few, elon- 

 gated, sheathing ; those of the stem diminishing upward, the uppermost bract- 

 like ; flowers mostly solitary, terminal ; divisions of the perianth oblong-obovate ; 

 capsule obtusely 3-angled ; seeds angular, brown. (Ixia ccelestina, Bartram.) 

 Pine barrens, Florida to South Carolina, and westward. May and June. Stem 

 1 - 2 high. Flowers bright blue. 



ORDER 148. DIOSCOREACEJS. (YAM FAMILY.) 



Twining herbs, with tuberous roots, ribbed and reticulated leaves, and 

 small regular dioecious flowers, in axillary spikes or panicles. Perianth 

 6-parted, the tube (in the fertile flower) adherent to the 3-celled ovary. 

 Stamens 6 : anthers 2-celled, introrse. Ovules anatropous, 1 - 2 in each 

 cell. Styles 3, more or less united below. Fruit mostly capsular, 3-6- 

 seeded. Embryo minute, in hard albumen. . 



1. DIOSCOREA, Plum. YAM. 



Tube of the perianth 3-winged. Stamens inserted at the base of the limb. 

 Capsule 6-seeded, mcmbranaceous, 3 winged, opening septicidally through the 

 wings. Seeds flat, broadly winged. Leaves petioled, mostly cordate and entire. 

 Petioles tumid at the base. 



1. D. villosa, L. Stem smooth (10- 15 long) ; leaves alternate, oppo- 

 site, or whorled, broadly cordate, acuminate, 7 - 9-nerved, smooth, or pubescent 

 l>eneath, mostly longer than the slender petiole ; flowers very small, whitish ; the 

 sterile ones in scattered clusters on the very slender branches of the axillary 

 panicles , the fertile in a simple spike ; stigmas notched at the apex ; capsule 

 oval or obovate, strongly 3-wingcd, nodding (D. quaternata, Walt.) Margins 

 of swamps, Florida, and northward. July. 



