HYPERICACEAE HYPERICUM 



631 



The oil of Hypericum is obtained from the European St. John's-wort (//. 

 perforatum) and is apparently found in the black dots of the petals and fruits. 

 The resin, however, found in the plant, is acrid and slightly bitter. The physiolog- 

 ical action of the St. John's-wort is : mental depression and exhaustion ; vertigo 

 and confusion of the head; dilation of the pupils, and increased heart action. 



Fig. 355. Great St. John's-wort {Hypericum 

 Ascyron). (Charlotte M. King.) 



VIOLACEAE. Violet Family 



Usually herbs or rarely shrubs or trees, caulescent or acaulescent, with al- 

 ternate, simple, entire or lobed leaves with stipules ; flowers mostly irregular ; 

 sepals 5; corolla of 5 petals, 1-spurred, hypogynous; stamens 5, short, fila- 

 ments broad and flat, often cohering with each other around the pistil ; ovary 

 simple, 1-celled, with 2 parietal placentae; fruit a capsule; seeds anatropous. 

 About 300 species, of wide distribution. The best known is the pansy (Viola 

 tricolor} running into numerous varieties, native to the Old World. It is some- 

 times used in skin diseases. The fragrant violet (V. odorata) is also frequently 

 cultivated. Some of our native species are very handsome. Among these are 

 the bird-foot violet (V. pedata), common in gravelly soils from Maine to Flor- 

 ida, west to Minnesota and Iowa and the V. pedatifida from Illinois to Kansas 

 and Minnesota. Our most common eastern yellow violet is V. pubescens; the 

 V. Nuttallii, also yellow, occurs from central Kansas westward. The white 

 Canadian violet (V. canadensis} is common in the north and in the mountains. 

 V. striata is common from the New England states to Minnesota and Missouri. 

 The white-flowered violet (V . blanda) occurs in swamps. Brazilian ipecac is 



