NABGISSALES. 



467 



Alisma and Sagitta/ria are two common genera. 



560. Cohort IX. Triurales, with one small and little 

 known order. 



Order Triuridese. — Delicate, almoat colorless herbs of tlie tropics. 



561. Cohort X. Bioscorales. — Climbing herbs or under- 

 shrubs, bearing reticulately veined leaves. 



Order Dioscoreacese. — The Yam Family. Several species of Dios- 

 eorea produce edible tubers. • 



D. saiiva, D. aculeata, and other species of India are extensively 

 grown there and in the West Indies as potatoes are grown in cooler 

 climates. 



D. Batatas and D. Japonica are known as Chinese Yams. 



Testudinaria elephantipes, of the Cape of Good Hope, is a curious 



Figs. 357-9. — Illttstratiosts op Alisma Plantago. 



Fig. 357. 



Fig. 367.— Flower cut vertically. Magnified. 



Fig. 868.— Seed. Magnified. 



Fig. 369.— Section of seed. Magnified. 



Fig. 358. 



Fig. 359. 



green-house plant, having a large, woody, above-ground corm-stem, 

 from which spring every year slender twining stems. 



562. Cohort XI. Tfareissales. — Plants with narrow, often 

 equitant leaves, having parallel venation ; seeds containing 

 endosperm. 



Order Hsemodoracese, — The Blood- wort Family. 



Order Amaryllidacese. — The Amaryllis Family. Distinguished 

 from the next order by having six stamens, and leaves which are not 

 equitant. The four hundred species are herbs of temperate and trop. 

 ical climates ; many possess a narcotic and poisonous principle. 



Agave Americana, the Century Plant of Mexico, is now much grown 

 in conservatories, and is said to be naturalized in Southern Europe. In- 

 Califomia,and its native country it blooms at the age of from ten to 



