1912.] Inheritance of Hoariness in Stocks (Matthiola). 



548 



and sap-colours containing one of the two hoary factors (assumed to be K*) 

 together with the colour-producing pair C, E. But since any one of the four 

 factors C, K, H, K can occur alone or with any combination of the others, 

 and also with either white or cream plastids, it becomes possible by appro- 

 priate breedings to obtain a large number of individuals identical in 

 appearance but differing in constitution. For, as shown in the accompanying- 

 table (Table I), we may have in the case of each of the glabrous non-sap- 

 coloured forms (i.e. white and cream) as many as 45 differerent types of 

 individuals, all alike to the eye and all breeding true : while a sap-coloured 

 strain may include 20 different types (see Table II), also indistinguishable 

 in appearance from one another.f Of these 65 types many have already 

 been identified, and it is merely a matter of applying the cross-breeding test 

 to a sufficient number of individuals in the F 2 generation to obtain the 

 remainder, for by this method alone, at present, are we able to detect the 

 presence of the non-effective factors and so ascertain the precise constitution 

 of any particular individual. 



Table II. — Showing the Constitution of the 20 different kinds of Individuals 

 which may occur in any Sap-coloured Glabrous Type. 



[1 



CEHk 

 CEHk 



[2 



CRhK 

 CEhK 



[3 



CEHk 

 CEhk 



[4 



CEhK 

 CEhk 



[5 



CEHk 

 CrHk 



[6 



CEhK 

 CrhK 



CEHk 

 cEHk 



[8 



CEhK 

 cEhK 



[9 



CEHk 

 cEhk 



[10 



CRhK 

 cRhk 



[11 



CEHk 

 erHk 



[12 



CEhK 



[13 



CEhk 

 CEhk 



[14 



CEhk 

 crhk 



[15 



CEHk 

 Crhk 



[16 



CRhK 

 Crhk 



[17 



CEhk 

 cRhk 



[18 



CEhk 

 Crhk 



[19 



CEHk 

 crhk 



[20 



CEhK 



The discovery of the fact that Fi derived from two glabrous sap-colours is 

 not invariably glabrous now makes it clear that no general statement can be 



* As we are unable to distinguish between H and K, the selection of K rather than 

 H is, of course, purely arbitrary. 



t Considered merely, i.e., from the point of view of the two characters under con- 

 sideration. If other characters are taken into account there would, of course, be many 

 more. 



