DIOSCOREA, a genus of plants of the order Diodeoreacem, which furnish the tropical esculents called yams. It is the type Of the natural order Dioscoreacere. The following Eastern speeies are generally recognised aculeata. damona. purpurea.
acutangula. fasciculata. pulehella.
alata. glabra. . rubella.
anguina. globosa. sativa.
atropurpufea. heterophylla. tomentosa.
belopbylla, nummularia. triphylla.
bullaifera. oppositifolia. • versicolor.
cirrhosa. pentaphylla. verticillata: crispata.
The yam planti, tire cUltivated in India, also among all the tribe's in the Archipelago, and generally most so where rice is least abundant ; but they nowhere form the chief bread Of the people, as ride, nriaize, or sago do. ' The Malay and Javanese names rubi or uwi extend to the languages of all the Malay and Philippine Islands, to those of the Pacific, and to 3ladagascar. In the Tonga it is ufi, in the Tahiti eui, in New Zealand uwi, in New Ireland u, and in Madagas car vwi. Madagaicar a wild yam is called uvi-ala, which is, without.donbt, the uwi-alas- the wild or forest yani of the Javanese, with the elision of the final consonant, cOnformably to the genius of Malagasi pronunciation. The word ubi, besides being applied specifically to the yam, is used as a generic for fariniceoui roots. Thud the batata, or Convolvulus batatas, is ealled bY the Malays uvi-jawa, or th e Javanese yam, to distillguish it from the Dioscorea. While many species are
nutritious in this genus, some are highly danger ous. D. dthmonum and D: triphylla, both ternate leaved Apecies, have very nauseous and dangerous tubers. In Otaheite, the D. bulbifera, which bears small fleshy angular, tubers along the stem in the axils of the leaves, is the favourite specieS. The elephant-foot yam, with a tuber about the size and shape of an elephant's foot, is white, and often as light and agreeable as a potato. It , abounds in Karen gardens, but is rarely seen among the Burmese, or in UM market. In Bengal, the species most. esteemed is D. globosa; after it D. alata, and next D. purpurea.
D. Crispata. Roxb. Myouk kya, BURM. A yam of Bengal. , D. Dinona. :Roxb. Ubium sylireitre, Bumph. Ko-wac, Burm. GroWs in Gorakhpur and the Moluccas. It is remarkable for its large ternate leaires, of which the leaflets are sometiinei nearly a foot long and. six inchei wide.
Dioscorea Japonica. ninth. baray yam et Japan and N.E. Australia.
D. Nummularia. Lanz. The Tivoli yam of con tinental and insular India and South Sea Islands roots exceedingly good.
Dioscorea oppositifolia. Linn. Of India and China ; an edible yam.,--Eng. Cyc. ; Crawfurd Diet. ;- Mason ; V. Illueller. . .