108 SIRKS, THE COLOURFACTORS OF THE SEEDCOAT IN PHASEOLUS 
violet or grey glow upon them. The B-factor would then, in 
KOOIMAN’s opinion, in heterozygotic state cause the inconstant, 
€versporting marbled pattern. 
6. PHASEOLUS MULTIFLORUS. 
About the colourfactors in the seedcoat of the scarlet-runnerbean 
and its varieties, our knowledge is more restrained and still less 
clear than it is concerning Ph. vulgaris. Besides brief and very 
incomplete communications of FERMOND and of KQERNICKE (as 
cited by FRUWIRTH 1919. p. 189), there is an observation of REINKE 
(1915), that would show the white colour as being dominant over 
the colouring of the seedcoat; because of the important cross- 
fertilization in this species (surpassing to a high degree that of the 
common gardenbean), some doubts about such an observation 
should always be held. Further indications may be found in the 
papers, mentioned above, of MENDEL and of TSCHERMAK, who 
gave (1912. p. 223) some numbers of segregation showing how 
uniformly coloured Fo- and Fs3-individuals may give a descendance 
of marbled and of selfcoloured plants, in proportions near 3:1, 
while brown-marbled would segregate still blackmarbled, totally 
blacks and totally violets, and the violet selfcoloured ones gave 
some descendants with black seedcoats. Coloured seedcoats would, 
according to TSCHERMAK be dominant over the absence of colour, 
or whites. And last, TJEBBES and -KOOIMAN (1919. p. 334). have 
told us about a hybrid between the constant marbled Ph. multi- 
florus (black pattern on a violet groundcolour) and a white seeded 
Ph. vulgaris, from which in Fo a.o. constant-marbled, marbled 
heterozygotes, constant selfcoloured and segregating selfcoloured 
individuals descended. The heterozygotes segregated along 3: 1. 
. The complexity of these results and the want of clearness con- 
cerning the genotypic factors at work in the seedcoats of these 
species, made a renewed research very desirable, chiefly in collec- 
ting many and precise. numbers of segregation in relatively simple 
crosses. In the present paper these researches are treated in 
connection with the conclusions, derived from them. 
