298 FOREST CULTURE AND 
tubers may be baked or boiled. It is this species 
which has been successfully cultivated in New Zea- 
land, and also in the Southern States of North Amer- 
ica. 
Dioscorea globosa, Roxburgh.—India. Roxburgh 
states this to be the most esteemed yam in Bengal. 
Dioscorea hastifolia, Nees. —Extra-tropic 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 aborigines for food. 
It is the only plant on which they bestow any kind of 
cultivation, crude as it is. 
Dioscorea Japonica, Thunberg.* (D. Batatas, De- 
caisne.)—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 yam 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 eylindrical, as thick as an arm; their taste ex- 
ceedingly good. 
Dioscorea oppositifolia, L.—India and China. Not 
prickly, One of the edible yams. 
Dioscorea pentaphylla, L.—Continental and Insular 
India, also South Sea Islands. Likewise a good yam. 
A prickly species, with alternate divided leaves. 
