tENoTHERA MUT. LATA AND (E. J\IUT. SEMILATA. 
525 
cut chiefly at a thickness of 10 /u and stained with Heiden- 
hain’s iron-alum-hasmatoxylin without a plasma stain. 
The chromosome counts were made as far as possible in 
pollen mother-cells undergoing the heterotypic and homo- 
typic mitoses, checked by a large number of counts from 
somatic prophase and metaphase stages in young petals or 
young ovary tissue. 
Material. 
In the following* table is given the pedigree number, 
history, and number of chromosomes in each plant examined. 
As mentioned above, these plants were all grown in 1912 at 
Merton. Under the pedigree number of each plant is given 
(1) the number of the culture, (2) in Eoman numerals, the 
number of the row in which the plant occurred, and (3) the 
number of the plant in the row. Thus, 228 .17.17 means 
plant number 17 in row IV of culture 228. Hence it is 
possible to refer to any individual plant by its pedigree 
number. 
From the table it will be seen that every plant having 
lata or semilata foliage characters has also 15 chromo- 
somes, and that this is quite irrespective of the source 
from which the plants came. In all, 21 plants having lata 
or semilata foliage were examined, and they originated 
in diverse races of CEnothera from Sweden, Hungary, 
Amsterdam, Madrid, and Birkenhead (England), both in pure 
races and in hybrid cultures. On the other hand, it is known 
from independent work of Greerts (1907), Gates (1907b), Lutz 
(1907) and Davis (1911), that the number of chromosomes in 
(E. Lamarckianais constantly 14 ; also that it is 14 in the 
mutants rubrinervis (Gates, 1908a), rubri calyx (here 
communicated), nanella (Gates, 1908b, Lutz, 1908), and in 
CE . brevistylis (unreported) and (E. laevifolia (Gates, 
1909b). The number 14 has also been shown to be present 
in the normal species CE. biennis L. (Gates, 1909b, and 
Davis, 1910) and in the other species CE. gran diflora 
