1889.] NATURAL SCIENCES OF PHILADELPHIA 357 



Order VIII. DIOSCOREAE. 



1. Dioscorea sativa, Griseb. 

 Common Yam. 



2. D. alata, Linn. 



White Yam Negro country Yam, and probably several other 

 species. D. sativa includes several varieties. Yams are indigenous 

 in all tropical countries, but the kinds cultivated for food appear to 

 have been introduced from the East Indies, though this is not 

 certain. 



3. Rajania hastata, Linn. 

 Wild Yam. In woods. 



Dioscoreae are chiefly and exceedingly valuable as food from the 

 abundant starch their root tubes contain. They contain an acrid 

 principle, which is removed by cooking. The leaves of some 

 species are used in intermittent fevers. 



Order IX. ALISMAOEAE. 



1. Sagittaria lancifolia, L. 



Arrow head. Indigenous. Sagittaria has the reputation of 

 being good for hydrophobia, mainly on account of its being a water 

 plant. The rhizomes when cooked are eatable. The members of 

 this family possess very astringent properties, and have been used 

 in the preparation of ink. 



Order X. JUNCAGINEAE. 



1. Triglochin, near T. striatum, R. & P. 

 This order is of no known use to man. 



Order XI. POTAMEAE. 



1. Potamogetonsp. T Pondweed. 



Pondweed. This order has no known properties. 



Order XII. NAITDEAE. 

 1. Thalassia Testudinum, Koen. 



Turtlegrass, Manatee grass. Marine. Serves as food for turtles, 

 and in Jamaica waters for the Manatee. 



Order XIII. PALMAE. 



1. Areca Catechu, L. 



Betel-Nut Palm.. One specimen in Nassau, called Pianang, 

 native of Cochin China, Malayan Peninsula and Islands. 



