164 ANTHOCYANINS AND GENETICS 



(a) Deep red stem, petioles and fruits: the teeth of the leaves 

 also tipped with red. 



(&) Brownish red stems, petioles and fruits, with no distinct red 

 borders to the leaves. 



(c) Green stems with reddish petioles and fruits. 



(d) Pure green stems, petioles and fruits. 



The red pigment is found: 



1. Chiefly in the parenchyma cells which lie immediately under 

 the epidermis of the stems and petioles. 



2. In the parenchyma of the petioles, sporadically, even as deep 

 as the phloem. 



3. In sub-epidermal cells near the margin of the leaf. 



4. In small multicellular hairs on the leaf and on the stipules. 



The intensity of coloration is due to the general distribution of the 

 pigment. Conversely, the fewer the pigment cells, the less red in the 

 stem. The authors point out that, in fact, there are only two real 

 colour types, red and green, since the classes (a), (6) and (c) are without 

 definite boundary lines. 



The results of crossing red races with green were as follows. When 

 pure green is crossed with a fixed red, red is dominant. In Fj the 

 hybrids appear to consist entirely of plants of one tint of redness, 

 which is less dense than the colour of the red parent. The red plants 

 of the F 2 generation vary widely in the amount of red colour they 

 contain. F 3 ,, from red F 2 , though fixed as regards red colour, shows the 

 same variation in intensity as F 2 . As a result of the experiments 

 examples were produced, either fixed or unfixed, of all intermediate 

 colour types of jute hitherto met with, including a pure fixed culture 

 of one of the commonest of these. 



Coreopsis tinctoria. De Vries (474) has shown that the yellow type 

 is dominant to the variety, 'brunnea,' in which the brown colour is 

 due to the development of anthocyanin. The type has evidently an 

 inhibitor of anthocyanin. 



Ci/pripedium (Paphiopedilum). Pigmented (anthocyanin) flower is 

 dominant to albino. Hurst (502, 531, 540, 596). 



Datura Stramonium. Saunders (475, 487) used two types, D. Tatula 

 having reddish stems and violet flowers, and D. Stramonium with green 

 stems and white flowers. The F t had red stems and violet flowers, 

 though the intensity of colour varied. In F 2 there was evidence of 

 typical Mendelian segregation. 



