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Digitalis purpurea, L. 
Greater part of Europe. The Fox-glove. A biennial and 
exceedingly beautiful herb of great medicinal value, easily 
raised. Chemical principles : Digitalin, Digitaletin and 
three peculiar acids. 
Dioscorea aculeata, L.* 
The Kaawi-Yam. India, Cochin-China, South Sea 
Islands. Stem prickly, as the name implies, not angular. 
Leaves alternate, undivided. It ripens later than the 
following species, and requires no reeds for staking. It is 
propagated from small tubers. This Yam is of a sweetish 
taste, and the late Dr. Seemann regarded it as one of the 
finest esculent roots of the globe. A variety of a blueish 
hue, cultivated in Central America (for instance at Caracas), 
is of very delicious taste. In the warmest parts of our 
colony this and the following species are likely to come to 
perfection. 
Dioscorea alata, L.* 
The Dvi-Yam. India and South Sea Islands. The stems 
are four-angled and not prickly. The tubers, of which 
there are many varieties, will attain under favorable circum- 
stances 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 culkrre 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 cul- 
tivated in New Zealand, and also in the Southern States of 
North America. 
Dioscorea globosa, Eoxburgh. 
India. Eoxburgh 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 
