II] Colours of Plants 39 



Brassica. White chromoplasts dominant to yellow in Swedes and 

 Turnips (Sutton, 262). 



Clarkia elegans. Common magenta-red dominant to salmon pink 

 (Bateson and Punnett). 



Coreopsis tinctoria. Ordinary yellow type dominant to var. brunnea 

 with brown flowers (de Vries, 290). The brown flowers like those of 

 Cheira7ithus (Wall-flower) are no doubt due to presence of much dark 

 anthocyan, and the case is probably one in which the development of little 

 anthocyan dominates over the development of much anthocyan (cp. 

 Lathyrus, Primula^ &c.). 



Datura. Purple in flower or stem dominant to white flower and green 

 stem (de Vries, 290; Saunders, 19). 



Gossypium. (Cotton). Dominance of many colour-characters in plant, 

 flower, and seed (Balls, 6). i^j details not yet published. 



Helianthus. Purple disk dominant to yellow disk (Shull, 241). 



Hordeum (Barley). Black pigment in paleae dominant to its absence 

 (Tschermak, 270; Biffen, 30). 



Hyoscyamus niger annuus x H. niger pallidus were found by Correns (69) 

 to give F^ flowers of intermediate tint. 



Zrt;//^jKr«j" (Sweet Pea). Anthocyan colours dominant. Purples dominant 

 to reds. Colour depends on two complementary factors. Yellow chromo- 

 plasts recessive to colourless. Facts fully described in later chapters. 

 Plants with coloured flowers have dark seed-coats. Whites have seed-coats 

 colourless. 



Lychnis. F^ between L. diurna and L. vespertina has flowers of inter- 

 mediate tint ranging through many grades (see de Vries, 290 \ Correns, 69; 

 R.E.C. 19). Segregation imperfectly studied. 



Matthiola (Stocks). Colours as in Sweet Pea (R.E.C. 19-21 ; 

 Tschermak, 278; Correns, 61). For colours of seeds see R.E.C. 19. 



Mirabilis. Colours consist of a complex series of reds and yellows, the 

 interrelations of which are not yet clear (see Correns, 67, 74, 77). Miss 

 Marryat's experiments (unpublished) prove the existence of a number of 

 heterozygous forms. 



Orchids. Dominance of anthocyan colour in Cypripedium is clear. 

 In that genus it results from union of two complementary factors (Hurst, 

 Gard. Chron. 1908, l. p. 173). As regards distribution of colour the facts 

 are complex, but several indications of Mendelian distribution have been 

 recognized (Hurst, 153, 160). See p. 96. 



Papaver. Presence of dark purple spot at base of petals dominant to 

 the absence of such colour (de Vries, 290). 



Phaseohis. The elaborate researches of Tschermak (271-3, 275, 278) 

 have demonstrated the existence of numerous factors controlling the colour 

 of the flowers and seed-coats in P. vulgaris^ P. multiflorus and their hybrids. 

 The flower-colours are purples, reds, and white, with a bicolour form of the 

 red ("Painted Lady"). Colour has not yet been produced by union of 



