Ernest Warren 
119 
In plants which had lost completely the power of producing any purple 
coloration whatever, the spots were brown and usually small and scanty, and 
among such plants an almost entire absence of spots of any kind occasionally 
occurred. We have already seen that with regard to the colour of the spots 
(brown and purple) Mendelian segregation takes place. 
In the inheritance of the amount of purple spotting no Mendelian relationship 
could be detected. The smallest amount of purple spotting met with in coloured 
foxgloves equalled about 1 %> '•^^^^^ the maximum about 10^/^. It will be re- 
membered that on crossing a dark purple plant with a plant bearing flowers very 
faintly tinged with purple (say, colour 4 of standard), definite segregation into 
" white " and purple plants occurred in the second generation following ; but on 
crossing a plant possessing an abundance of purple spots (say, 50 °/^) with a plant 
bearing very few purple spots (say, 2 °/,^ or 3 °/^) no such segregation was found, 
and the spotting tended to remain intermediate in amount. 
In the numerous crosses that have been made for various purposes the con- 
dition of the spotting was observed, and it is undoubtedly true that the means of 
the spotting of the families resulting from the crosses tended on the average 
to approximate to the spotting of the mid-parent, ^ {^^ + $ ) No difference could 
be detected between the reciprocal crosses of two plants. 
Influence of Selection and Strength of Inheritance in Self fertilised Generations. 
In this connection details of Series II and III may be given (see p. 120). Plant 
Ci with 11 7o spotting was crossed with pollen of plant with spotting 48 "/^ = II. 
Seven of the offspring were selfed and the spotting of the resulting fixmilies was 
determined. Subsequently two other generations were raised by selfing. Plant 
was crossed with pollen of = III. Four of the offspring were selfed and sub- 
sequently three other generations were raised by self-fertilisation. 
The distributions of the spotting in the families of the different generations are 
shown in the accompanying table. In each generation the families are arranged 
in the ascending order of the parental spotting (see the top and middle horizontal 
lines). A casual inspection indicates at once that the general trend of the family- 
distributions follows the gradual increase in the spotting of the parents. 
As an example of selection we may take : 
III 2 (9 7 J selfed produced with others a plant TII 2, 5 (15 7 J 
III 2, 5 (15 7J selfed „ „ „ III 2, 5, 10 (22 7J 
III 2, 5, 10 (22 7J selfed „ „ „ III 2, 5, 10, 17 (27 7J 
III 2, 5, 10, 17 (27 selfed produced a family with mean spotting of 39 '7o 
Thus, we have passed from a plant with 9 7o spotting to a plant with 27 7o; 
which on selfing produced a family with a mean spotting of 39 °/^. 
With reference to the strength of inheritance two tables are given on p. 121, 
one for parents and offspring, and one for grandparents and grandchildren. The 
respective coefficients of correlation are '560 and "395. This correlation does not 
arise by the mixture of two races which have been sorted out by segregation 
