1918] DEVRIES—MASS MUTATIONS 379 
somes in its nuclei. As was to be expected, besides this gigas there 
was also found a semigigas, but since it was wholly sterile, little 
weight can be attached to it. Gares (10) observed a dwarf mutant 
of O. grandiflora, but no dwarf occurred among my cultures. 
The pedigree of the whole culture is as follows. All fecundations 
were pure self-fertilizations, made by myself. 
First generation Second generation Third generation Fourth generation 
IQI2 IQI3 1916 
ochracea ————ochracea~————ochracea 
lorea ———-——_lorea ——————_lorea 
Alabama———grandiflora ochraces 
lorea 
lorea 
deatdidors — grandiflora — | grandiflora 
os ochracea 
semigigas 
gigas 
gigas ———— gigas-lorea 
gigas-ochracea 
The numbers of specimens and the percentages of the splitting 
in this pedigree are shown in table I. 
TABLE I 
. Number of | P. Percentage 
Generation aiaciaane cchcaaie yg 
grandiflora OR a ey ale es ye 
s 2 1476 (20) 2 
7 3 180 44 I 
4 53 (15) 4 
Pe eee 2 123 = 2:5 
ochracea 2 380 uniform ie ae 
ce 
3 es 
a te ee 2 100 ike uniform 
“ cé 
ee 3 61 siiese Pee 
The control lines were derived from different specimens, grown 
in 1913 from the seed of Castleberry. They yielded the same two 
main mutants as given in table I. In the spring of 1914, however, 
before I discovered the presence of mutants, I had observed that a 
large number of the seedlings were very weak, dying off during the 
