'•'^ 



264 BOTANY AND PHARMACOGNOSY. 



is somewhat fusiform, reddish-brown and with a bitter, astringent 

 taste. It contains chrysophanic acid, tannin, calcium oxalate and 

 some of the other constituents found in rhubarb. 



Rumex Acetosella (field or sheep sorrel) is a slender annual! 

 herb with hastate leaves, having flowers in compound racemes.. 

 The leaves contain oxalic acid, both free and in combination with 

 calciimi and potassium. 



Tannin is obtained from a number of the plants belonging to 

 the Polygonacese, as the root of Rumex hymenosepahts of 

 Texas which is known as Canaigre; the rhizome of Polygomtm 

 bistorta of Europe which yields the drug Bistorta. 



The leaves of Polygonum orientale of China and other parts- 

 of Asia are smoked like tobacco. Polygonum rivulare of the East 

 Indies is used as a fish poison. The following yield indigo : 

 Polygonum alatum of tropical and' sub-tropical Asia and Africa, 

 and P. tinctorium of China. P. Hydropiper and P. aviculare, 

 both common in the United States, are poisonous to sheep. The 

 latter plant when eaten by cows gives a blue color to the milk. 



A number of the plants of this family yield ^'food products. 

 Buckwheat is the fruit of Fagopyrum esculentum' indigenous tO' 

 Central Asia and cultivated in many parts of the world. 



Some are also cultivated as ornamental plants, as the Prince's, 

 feather {Polygonum orientale). 



XL ORDER CHENOPODIALES OR CENTROSPERM^. 



This order includes seven families, in all of which the embryo 

 is curved or coiled, and the reserve consists chiefly of perisperm. 



a. CHENOPODIACE^ OR GOOSEFOOT FAMILY.— 

 The plants are annual or perennial herbs with simple leaves and 

 small perfect flowers, the fruit being a utricle. The fruits of a 

 number of the group contain volatile oil, and are used in medi- 

 cine, as the common wormseed (Chenopodium anthelminticum) , 

 which is found in waste places in the United States, an allied spe- 

 cies C. ambrosioides, and other species of Chenopodium as well. 

 Spanish wormseed is obtained from Anabasis tamariscifolia. 



Chenopodium mexicanum yields saponin. Atriplex hortensis 

 of Tartary" yields indigo. The ash of very many species of 



