Vol. X, No. I.] The Dioscoreas of the Old World. 39 



[N.S.] 



100. D. persimilis, Prain et Bui kill, in Journ. Asiatic 

 Soc. Bengal, i v. (1908), p. 454. S.mth-ueste.n China, south- 

 eastern China and Tonkin. 



101. D. Hamiltonii, Hook, f., Flor. Brit, hid., i v. (1892) 

 p. 295, in chief part: Prain, Bengal Plants, ii. (1903) p. 1067* 

 D. acutangula, Hani, in Her!.. Wall. D. acutanguli flora, Stem! 

 in Herb. Ind. Or. Hohenacker. D. Hookeri, Prain in Records 

 Bot. Survey Ind., ii. (1902), p 143. In the moister parts of 

 India, e.g. Sikkim, Assam, northern Burma, Arakan. the Shan 

 plateau and Tenasserim, also in the Circars and Orissa and in 

 the Western Ghats from North Kanara to Travancore. In the 

 Flora of British India it has not been clearly distinguished from 

 the following species. 



102. D. alata, Linn., Spec. Plant., (1753), p. 1033. D. 

 atropurpurea , D. globosa, D. purpurea and D. rubella, Roxb 

 mot Ind., iii. (1832), pp. 797-800. D. Bicantaca, D. Devipata, 

 I). Hurchusia and D. octangular is, Ham. in Herb. Wall Culti- 

 vated throughout the Tropics, wherever the rainfall is sufficient. 

 It is certainly of eastern origin and was perhaps derived from D 

 Hamiltonii. In the Western Himalaya races exist, here classed 

 under var. Tarn, which appear as if D. belophylla may possibly 

 enter their composition. A plant widely cultivated is com- 

 monly polymorphic as regards the parts subjected to man's 

 influence ; and D. alata is no exception : it shows a great 

 variety of forms of tuber. Roxburgh sub divided the species 

 by the shape of the tuber and by their colour, knowing only 

 those which are commonly cultivated in Lower Bengal: and 

 Hamilton followed Roxburgh's lead. Wider knowledge makes 

 it inconvenient to maintain Box burgh's and Hamilton's species 

 even as varieties. D. alata sometimes flowers and very rarely 

 fruits. It readily persists in a wild state in moist regions 

 atter the desultory cultivation of jungle tribes, maintaining 

 itself by means of its tubers : naturally it is the deeper rootin^ 

 races which most of all persist, the others being soon grubbed 

 up by wild animals. 



Variat : — 



Var. Tarri Vence in pagina inferiore foliorum conspieu*. 

 Var. vera. Vence minus conspicuse. 



Varietas Tarri colitur in Kamaon et in parti bus adiacentibus mon- 

 tium Himalaicorum. 



103. D. laurifolia, Wall., Cat. Lith., (1832), no. 4111 : 

 Hook. (., Flor. Brit. Ind., vi. (1892), p. 293. D. oppositifolia , 

 Curtis, Flowering Plants and Ferns Penang, (1894), p. 83. 

 Malay Peninsula, being common in the island of Singapore. 



104. D. Havilandii. D. cornifolia, Ridley, Mat. Flor. 

 Malay Penins., ii. (1907), p. 81, as regards the fruit only. 



