CLASSIFICATION OF ANGIOSPERMS. 489 



Draco, is obtained from Dracccna Draco, a tree growing in the 

 Canary Islands. Some of the trees of this species are of historic 

 interest, as the dragon tree of Orotava, which is 46 feet in circum- 

 ference at the base. 



A number of the plants of t this family contain saponin, as the 

 species of Smilax. Some contain coniferin and vanillin, as Aspar- 

 agus officinalis. Some of the group contain glucosidal principles 

 which under the influence of ferments yield ethereal oils contain- 



FIG. 270. A field of Aloe plants, growing in the Riversdale District, Cape Colony. 

 The stems are simple, with one or more clusters of leaves; the latter are from 3 to 6 dm. in 

 length, fleshy and very thorny-prickly at the margin. Reproduced by permission of the 

 Philadelphia Commercial Museum. 



ing sulphur, as the various species of Allium. Garlic (Allium 

 sativum) contains a glucoside, allisin, which on hydrolysis with an 

 oxidase (allisin) forms the essential oil of garlic. A number also 

 are quite poisonous when fresh but edible when cooked. 



b. AMARYLLIDACE^: OR AMARYLLUS FAMILY. 

 This group is of special interest because it includes the Agave 

 or Century plant. This is a characteristic genus of plants of the 

 hot and arid regions of North America. The best known of these 



