293 

 Digitalis purpurea, L. 



Grreater part of Europe. Tlie Pox-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-Tam. 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 Uvi-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 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 cul- 

 tivated in New Zealand, and also in the Southern States of 

 North America. 



Dioscorea globosa, Eoxburgh. 



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 



