ANTHOCYANINS AND GENETICS 153 



is red-flowered. Cheiranthus Cheiri, also, in the wild state is only tinged 

 with brown (anthocyanin), and from it in cultivation have appeared 

 varieties fully coloured with anthocyanin of deep shades of brown 

 and purple. In Crataegus Oxyacaniha (Hawthorn) the white-flowered 

 type has produced a red-flowered variety. In Cyclamen persicum the' 

 type has white flowers with a basal magenta spot on the petals and has 

 given rise to varieties with fully-coloured magenta and crimson flowers. 

 In Helianthemum vulgare, Primula acaulis (Primrose) and P. veris 

 (Cowslip), the types are yellow and the varieties both crimson and 

 magenta. Further examples are Freesia and Acliillea MiUefolium (de 

 Vries, 498) with coloured flowers. De Vries (498) also notes this phe- 

 nomenon. He says: "a pink-flowered variety of the ' Silverchain' or 

 ' Bastard- Acacia ' (Robinia Pseud-Acacia) is not rarely cultivated. The 

 'Crown' variety of rice, oats and barley are also to be considered as 

 positive color-variations, the black being due in the latter cases to a 

 very great amount of the red pigment." And again : "The best known 

 instance is that of the ever-flowering begonia, Begonia semper florens, 

 which has green leaves and white flowers, but which has produced 

 garden varieties with a brown foliage and pink flowers." Cockerell (602, 

 603, 611) has also drawn attention to a red-flowered variety of Helianthus 

 of which the type is yellow. Again, the red colour may be developed in 

 the carpels as in the varieties of Primula with red stigma (Gregory, 557) 

 and the purple-podded forms of Pisum and Phaaeolus. The variety 

 appears in other fruits too (the ' Blood Orange ' and the red Banana) ; 

 also in the Gooseberry, Ribes Grossularia (de Vries, 498). 



Another phenomenon which sometimes appears in variation is that 

 which may be termed partial albinism ; the type has coloured flowers 

 but the variety has white flowers, though all the vegetative organs may 

 still form anthocyanin. This is the case in the blue Vinca minor with 

 its white-flowered variety of which the corolla is slightly tinged with 

 purple. Of Geranium Robertianum (Herb-Kobert), also, there is a 

 white-flowered variety with red stems and leaves. A similar variation 

 is sometimes found in the native flora, i.e. Polygala vulgaris, Jasione 

 montana, and others, but it is not really possible, in the absence of 

 Mendelian evidence, to distinguish these varieties from the tinged 

 varieties already mentioned. Partial albinos, moreover, are similar 

 in appearance to types in which anthocyanin is inhibited; but an 

 important distinction lies in the fact that partial albinos cannot give 

 rise to coloured varieties though inhibited types may. 



A case difficult to place is that of the dominant or inhibited white 



