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account deserves particularly to be drawn into culture. 

 The tubers are largely consumed by the aborigines for 

 food ; it is the only plant on which they bestow any kind of 

 cultivation, crude as it is. 



Dioscorea Japonica, Thunberg.* (JD. Batatas, Decaisne.) 



The hardy Chinese and Japan Yam. This species, which is 

 not prickly, has been cultivated some years in our Botanic 

 Garden. The material here for comparison is not complete, 

 but seems to indicate, that D. transversa, R. Br. and D. 

 punctata, R. Br., are both referable to D. Japonica. If 

 this assumption should prove correct, then we have this Tarn 

 along the coast tracts of North and East Australia as far 

 south as latitude 33°. In Australia we find the wild root of 

 good taste. 



Dioscorea nummularia, Lamarck. 



The Tivoli Yam. Continental and Insular India, also South 

 Sea Islands. A high climbing prickly species, with opposite 

 leaves. Roots cylindrical as thick as an arm ; their taste 

 exceedingly good. 



Dioscorea oppositifolia, L. 



India and China. Not prickly. One of the edible Yams. 



Dioscorea pentaphyila, L. 



Continental and Insular India, also South Sea Islands. Like- 

 wise a good Yam. A prickly species, with alternate divided 

 leaves. 



Dioscorea purpurea, Roxb. 



India. In Bengal considered next best to D. alata. 



Dioscorea sativa, L. 



South Asia, east as far as Japan, also in the South Sea 

 Islands, and North and tropical East Australia, likewise 

 recorded from tropical Africa. Stem cylindrical, not prickly. 

 The acrid root requires soaking before boiling. It has proved 

 hardy in the Southern States of North America. 



Dioscorea spicata, Roth. 



India. Root used like those of other species. 



