258 ROCK GARDENING FOR AMATEURS 



V. biflora, native of Europe, is a tiny plant with two- 

 flowered stems of bright yellow blooms in May and June. 

 It needs a moist place and partial shade. The Spurred 

 Viola, found wild in Europe, V. calcarata, has purple or 

 white flowers in spring ; it likes a half-shady spot. 

 V. cornuta, the Horned Viola, from the Swiss and other 

 mountains, flowers throughout spring and summer ; the 

 blooms vary from white to mauve, blue and purple. 

 It is too vigorous for a choice spot. Purple Robe and 

 Papilio are good varieties. The lovely Grecian Viola 

 gracilis has purple flowers in spring and summer, and 

 will grow almost anywhere, though preferring slight 

 shade. For a hot, dry bank V. hirta, 

 native of Europe, with blue, white, 

 or red-purple flowers in spring, and 

 of the type of our common Violet, 

 is useful. V. odorata is, of course, 

 the Sweet Violet of gardens, and 

 is welcome on rockwork. V. pedata, 

 a North American kind, loves a 

 well-drained, peaty soil. It has 

 lovely blue flowers in spring ; the 

 white variety, alba, is very fine. 

 Other good Violas are V. cenisia, 

 the Mont Cenis Violet, blue ; the 

 Canadian V. canadensis, of taller 

 growth, blue and white ; V. lutea, 

 yellow ; V. pinnata, a distinct kind 

 A Rock.Garden viola with blue flowers and pretty foliage ; 



