290 Miss M. Wheldale. The Inheritance of [Feb. 12, 



4. Ivory is " dominant "* over yellow ; a zygote containing Y and I or Y, I, 



and T, is ivory. 



5. Since magenta superposed upon yellow gives crimson, a zygote 



containing Y, L, and T is crimson, Y and L only, crimson delila. 



6. Magenta superposed upon ivory gives, since the latter is very pale, 



magenta. A zygote containing Y, I, L, and T is magenta, Y, I, and L 

 only, magenta delila. 



The five types described are readily distinguishable and quite discontinuous. 

 Throughout the experimental work, all individuals met with have been at 

 once assigned, without any difficulty, to one of the above classes. Magenta 

 colour, however, appears in at least three distinct shades or degrees of 

 concentration, which are probably determined by definite factors, though 

 evidence on this point is not yet complete. Upon a yellow ground, these 

 shades of magenta give the corresponding shades of crimson. In many cases 

 deep magentas have been bred from the lighter magentas, so we must conclude 

 that lighter forms are dominant to darker in the same sense that the pale 

 form, ivory, is dominant to yellow. Similar phenomena have been found to 

 occur in Sweet Peas and Stocks.f 



The concentration of sap-colour in the tube and lips is generally approxi- 

 mately the same ; the lips are somewhat darker in appearance, but this 

 difference depends probably on texture and not on difference in depth of 

 pigmentation. The tube may also be darker in shade than the lips, and this 

 is the case in one or two types not yet investigated. 



The magenta sap-colour sometimes appears in irregular neckings or 

 stripings, thus giving striped forms. If the striping occurs in the magenta 

 type, the ivory ground-colour shows where the magenta sap fails and the 

 flower may be described as ivory flecked or striped with magenta. When the 

 magenta sap fails in the crimson type, the yellow ground-colour appears and 

 the flower would be described as yellow flecked or striped with crimson. No 

 flecking or striping of ivory on yellow has ever been observed. 



In several cases, where striped and non-striped forms have been crossed, 

 striping has disappeared in Fi, and has not appeared again either in F 2 or F3. 

 In another case of striped x non-striped (a paler magenta), the deeper striping 

 persisted in Fi on the paler magenta ground ; a striped Fi has been given 



* " Dominant " is here used to denote that the lighter colours overlie or suppress the 

 darker, as ivory, for example, conceals yellow ; and not in its strict sense of expressing the 

 relationship between a pair of allelomorphic characters : ivory and yellow are not, of 

 course, allelomorphic to each other. 



t 'Third Eeport to the Evolution Committee,' W. Bateson, E. E. Saunders, and 

 E. C. Punnett, p. 4. 



