STUDIES ON THE GENETICS OF FLOWER-COLOURS, ETC. 
119 
In each of these crosses their T^-ofispring are composed approximately of 3 
dominants and 1 recessive, and the fact that in each of the above (3) we 
have a monohybrid instead of a dihybrid segregation is explained by the 
assumption that in Aquilegia A and J>, and in the Rabbit C and S are in 
absolute linkage. This explanation, though yet hypothetical, seems to me not 
improbable in view of my results in the cross magenta x orange just mentioned, 
because in the latter case the absolute linkage exactly similar to that assumed 
in Aquilegia and the Rabbit has been, not merely assumed, but adequately 
proven. 
Morgan and his school are inclined to explain the case of Aquilegia and 
the Rabbit above given by means of their theory of multiple allelomorphism. 1 
I will not enter here into the discussion which of the two alternative hypotheses 
will better explain the above cases, but I will simply state that what I have 
observed in respect to the cross in Portulaca corresponds exactly to what the 
hypothesis advanced by Baur and Punnett demands. 
Note on the so-called “ pseudo-white ” Race. 
Pseudo-wliite is the name given to a peculiar race of white colour which 
has newly arisen in my culture. In this race leaves and stems are reddish 
as in coloured varieties, but the corolla is white, though slightly flashed with 
magenta, especially in its periphery, and each petal is generally furnished with a 
magenta spot at its basal part (“ Herzfleck ” of German authors); filaments, 
styles and stigmas are reddish (PL II, fig. 6). This race may belong either 
to that type in which the production of anthocyanin is inhibited, or to that 
which Miss Wheldale calls “ partial albino.” 2 One pseudo-white was produced 
in the i^-ofispring ex white-II x magenta (s. the Table Y), in all probability 
by mutation, but it may be produced regularly in the offspring of certain 
crosses of wliite-IH, and very probably according to Mendelian rule : thus, for 
instance, the cross orange X white-III lias been followed up till F -, and tliis 
fact has been made probable, though the details of the results obtained by me 
will not now be published, because they are yet far from complete. Below I 
1 The Mechanism of Mendelian Heredity. New-York, 1915, pp. 157 ; also, Stuetevant, Amer. 
Naturalist, Yol. 47, 1913. pp. 234-238. 
2 The Anthocyanin Pigments of Plants, Cambridge 1916, p. 153. 
