100 SELECT PLANTS FOR INDUSTRIAL CULTURE 



are many varieties, will attain, under favourable circumstances, 

 a length of 8 feet, and the prodigious weight of one 

 hundred pounds ! This species and the preceding one are 

 the two principal kinds cultivated in tropical countries. 

 D. alata is in culture supported by reeds. It is propagated 

 from pieces of the old root, and comes in warm climes to 

 perfection in about seven months. The tubers may be baked 

 or boiled. It is this species which has been successfully 

 cultivated in New Zealand and also in the Southern States 

 of North America. 



Dioscorea glabra, Roxburgh.* (D. Batatas } Decaisne.) 



The Chinese Yam. From India to China. Not prickly. The root 

 is known to attain a length of 4 feet, with a circumference of 14 

 inches and a weight of about 14 Ibs. The inner portion of the 

 tuber is of snowy whiteness, of a flaky consistence, and of a 

 delicious flavour ; preferred by many to potatoes, and obtained 

 in climes too hot for potato crops. The bulbilles from the 

 axils of the leaf -stalks, as in other Dioscoreas, serve as sets 

 for planting, but the tubers from them attain to full size only in 

 the second year, the produce being in proportion to the set 

 planted. The upper end of the tubers offers ready sets, but there 

 are dormant eyes on any portion of the surface of the tubers 

 (Sir Samuel Wilson ; General Noble). First grown here by 

 the author in 1858. 



Dioscorea globosa, Roxburgh. 



India. Roxburgh states this to be the most esteemed Yam in 

 Bengal. 



Dioscorea hastifolia, Nees. 



Extra-tropical Western Australia, at least as far south as 32. 

 It is evidently one of the hardiest of the Yams, and on that 

 account deserves particularly to be drawn into culture. The 

 tubers are largely consumed by the local aborigines for food ; 

 it is the only plant on which they bestow any kind of cultiva- 

 tion, crude as it is ; fit for arid situations, but seemingly fond 

 of lime. 



Dioscorea Japonica, Thunberg. 



The hardy Japan Yam. Not prickly. 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 Yam along the coast tracts of North and East 



