634 A TEXT-BOOK OF -BOTANY 



the Meadow beauty (Rhexia). Quite a number of the plants are 

 cultivated and a large number yield edible fruits. The fruits, 

 barks and leaves frequently contain COLORING PRINCIPLES. A yel- 

 low coloring principle is found in the leaves of a number of species 

 of Memecylon of the East Indies and Africa, which resembles 

 that of saffron and curcuma. Red coloring principles are found 

 in the berries of a number of species of Blakea of South America. 

 A black coloring principle is obtained from the fruit of several 

 species of Tamonea of tropical America, Melastoma malabathri- 

 cum of the East Indies and Tococa guianensis of Northern South 

 America and Tibouchina Maxvmiliana of Brazil. Tannin is found 

 in considerable quantity in the barks of Tibouchina, Dissotis and 

 Rhynchanthera. 



The leaves of Tamonea thecczans are used in Peru as a Sub- 

 stitute for tea. A mucilage is found in the bark of Medinilla 

 crispata of the Molucca Islands. The flowers of the latter plant 

 as well as of M. macrocarpa are used as a remedy for the bite of 

 poisonous serpents. 



/. ONAGRACE/E OR EVENING PRIMROSE FAMILY. 

 These are mostly annual or perennial herbs with usually entire 

 or toothed, simple leaves. The flowers are perfect, regular or 

 irregular, epigynous, variously colored, solitary in the axils of the 

 leaves or in somewhat leafy spikes. The fruit is a dehiscent 

 capsule, berry, drupe, or nut. This family is represented in tem- 

 perate regions by such plants as the Willow herb (Epilobium), 

 Evening primrose (CEnothera), on which de Vries has carried on 

 his famous mutation experiments, and Enchanter's nightshade 

 (Circaea). The cultivated FUCHSIA also belongs to this family. 

 A yellow coloring principle is obtained from the herb and unripe 

 fruits of Jiissicua pilosa of Brazil. The roots of CEnothera bien- 

 nns, O. muricata and other species of this genus are edible. 



This family also includes the group of aquatic plants, repre- 

 sented by a single genus and one of which, Trapa natans or Water 

 chestnut, is naturalized to some extent in the ponds of Massachu- 

 setts and New York. The fruit is coriaceous, 2- to 4-spinose, and 

 i -seeded. The cotyledons are unequal, rich in starch, and are 

 edible, sometimes being ground and made into bread by the people 

 of Europe and Northern Asia. 



