HYPERICACEAE HYPERICUM 



631 



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

 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 



