NARGI8SALES. 46? 



Alisma and Sagittaria are two common genera. 



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

 known order. 



Order Triurideae. Delicate, almost colorless herbs of the tropics. 



561. Cohort X. Dioscorales. Climbing herbs or under- 

 shrubs, bearing reticulately veined leaves. 



Order Dioscoreaceae. The Yam Family. Several species of Dios- 

 eorea produce edible tubers. 



D. sativa, 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 elephantipcs, of the Cape of Good Hope, is a curious 



FIGS. 357-9. ILLUSTRATIONS op ALISMA PLANTAGO. 



FIG. 357 



Fig. 357. Flower cnt vertically. Magnified. 



Fig. 358.-Seed. Magnified. 



Fig. 359. Section of seed. Magnified. 



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

 from which spring every year slender twining stems. 



562. Cohort XI. Narcissales. Plants with narrow, often 

 equitant leaves, having parallel venation ; seeds containing 

 endosperm. 



Order Haemodoraceae. The Blood- wort Family. 



Order AmaryllidaceaB. The Amaryllis Family. Distinguished 

 from the oext 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 

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



