292 DIOSCOREACEiE. Sisyrinchium. 



leaflets linear-lanceolate, tapering to a mucronate point ; in var. 1 , they are about three-fourths 

 of an inch long, somewhat equal, and shorter than the flower, but often longer than the 

 pedicels, sometimes purplish ; in var. 2, the outer leaf is often 1^-2 inches long, ex- 

 ceeding the flowers, and more frequently tinged with purple or violet. Flowers 2-5 from 

 each spathe, opening in succession, fugacious. They are about half an inch in diameter, of 

 a dehcate purplish-violet, with a small yellow centre, and are supported on slender pedicels. 

 Segments of the perianth emarginate, with a central cusp. Stamens shorter than the perianth ; 

 the filaments at first cohering : anthers linear ; the cells distinct at the base. Style closely 

 surrounded by the stamens : stigmas a little spreading. Capsule globose and obscurely 3-sided, 

 the size of a small pea. Seeds about 8 in each cell, in a double row, globose-angular. 



In moist meadows, among grass, and in woods. Fl. End of May -June. Fr. July. The 

 two plants which I have here described as varieties, are considered distinct species by most 

 of our botanists, but there are many intermediate forms which seem to connect them. 



Order CXV. DIOSCOREACEtE. K. Brown. The Yam Tribe. 



Flowers mostly dioecious. Perianth 6-cleft or -parted, in a double series. Stamens 

 6, or sometimes 3. Ovary adherent to the tube of the perianth, 3-celled, 

 with one or two anatropous ovules in each cell : styles 3, united below or 

 distinct. Fruit capsular, often 3-lobed or 3-winged ; two of the cells some- 

 times abortive. Seeds flat, sometimes winged. Embryo minute, lying in a 

 cavity of the cartilaginous albumen. — Twining herbs or undershrubs. Leaves 

 with reticulated veins, peliolate. Flowers inconspicuous. 



1. DIOSCOREA. Plum.; Endl. gen. 1201 ; Griseb. Smil. ^ Diosc. in Endl. <^ Mart. 



fl. Bras. p. 24. yam. 



[Dedicated to the ancient Greek naturalist Dioscobides.] 

 Dioecious. Sterile fl. Stamens 6 (3 of them sometimes barren) or only 3 : filament subu- 

 late : anthers globose-didymous. Fertile fl. Styles distinct nearly to the base : stigmas 

 linear, spreading. Ovary 3-celled, with 2 ovules in each cell. Capsule membranaceous, 

 3-celled, triangular, with broad somewhat winged angles. Seeds membranaceously winged. 

 — Twining herbs or undershrubs. Rhizoma tuberous, often very large. Leaves' mostly 

 alternate, sometimes opposite, cordate or hastate. Flowers very small, numerous, in 

 axillary panicles or spikes. 



