VARIATION OF COLOUR IN WILD PLANTS. 327 



flowers ; and Myosotis palustris has both yellow and blue 

 flowers. My friend Mr. Dickson, of Jersey, has also found 

 a specimen of (Enothera biennis, with eight flowers on it ; 

 six of the usual yellow colour, one purple, and the other 

 blue. The second, or Cyanic class, has hliie for its type, 

 which can pass into red or white, but never into yellow, 

 Schubler and Funk consider green as a sort of neutral colour, 

 intermediate between these two classes. Most purple or 

 blue flowers may have red or white varieties ; rose-coloured 

 flowers seem the next most liable to variation ; while yellow 

 rarely change : Glaucium luteum has been gathered, how- 

 ever, by Mr. Dickson, with flowers of a white colour ; and 

 several other varieties in this type of colour have already 

 been mentioned. The cause of the non-oxygenation of white 

 varieties is not well understood. It cannot be ascribed to 

 the absence of solar light, as many of them are found grow- 

 ing in very exposed situations : nor are the subjects of this 

 variation weakly and frail, hke plants that have been submitted 

 to the process of blanching. It cannot be owing to the same 

 cause that produces a white colour in many animals of the 

 northern regions, namely cold, as many of these white speci- 

 mens are found in the summer, and all of those mentioned by 

 us, were observed in the mild temperature of the British Is- 

 lands. We are constrained, therefore, to assign them to cer- 

 tain unknown causes, which induce in the floral envelopes of 

 plants a white colour, perhaps somewhat analogous to those 

 which produce albinoism in the animal kingdom. 



The following white varieties met with in wild British plants, 

 belong to the Cyanic series of De CandoUe ; that is, their flo- 

 ral envelopes are naturally coloured blue, rose-coloured, or 

 purple. They have been observed both by myself, and also 

 by Mr. O. A. Moore, of York. I have thought it better to 

 throw the plants into their natural orders : — 1. Ranunculaceae, 

 Ranunculys Flammula ; Anemone nemorosa (every stage, 

 from purple to white). — 2. Violaceae, Viola odorata (various 

 shades from dark blue to white). — Polygalacese, Poly gala vul- 

 garis (also pink). — 4. Caryophyllaceae, Lychnis dioica (red, 

 rose-coloured, and white). — 5. Geraniaceae, Geranium pra- 

 tense ; G. phceiim ; Erodium cicutarium.^^ — 6. Ericaceae, 

 Menziesiapolifolia ;* Andromeda polifolia ;* EricaTetralix', 

 Calluna vulgaris. — 7. Leguminaceae, Ononis arvensis ; Tri- 

 folium pratense, — 8. Rosaceae, Geumrivale (also yellow). — 9. 

 Circaeaceae, Circwa lutetiana (white and pale red). — 10. Me- 



' The varieties marked with an * I have not^met with ; they were kindly 

 supplied by Mr. Moore. 



