248 BOTANICAL GAZETTE [ocroBER 
it is visible in a much smaller percentage of the cases. Consider- 
ing the size of this chromosome, it is to be expected that in some 
cases it should be obscured from vision by the other chromosomes 
(figs. 7, 8, 14, 17). 
FARMER, BOLLETER,’ EscovEz, and Woopsurn’® report eight 
chromosomes in the haploid nucleus, and in my preliminary note? 
J suggested the possibility of a variation as to chromosome number 
in this species. More recent studies in plants from Ithaca and 
from Copenhagen make it seem quite certain that the same number 
of chromosomes is to be found in the plants of this species in those 
regions. It seems probable, therefore, that these investigators have 
overlooked the small chromosome, a thing which might easily 
have happened, especially since they were interested primarily in 
other phenomena. 
A comparison of the chromosomes -of one sex with those of the - 
other shows no perceptible difference, either in the number or size 
relations, as may be seen by comparing figs. 1, 2, 4, 7, 9, and 18 
(female) with figs. 3, 5, 6, 8, and 10 (male). Although this condi- 
tion of like chromosomes in the two sexes in Conocephalum is not 
an evidence against the sex chromosome basis of sex inheritance 
in the dioecious Bryophyta, it does show that the marked differ- 
ence between the chromosomes of the two sexes in Sphaerocar pos 
is not a universal condition among these plants. 
Summary 
1. The chromosome number in the gametophyte of Cono- 
cephalum conicum (L.) Dum. is nine instead of eight as reported 
by previous investigators. 
2. The chromosomes vary considerably in size, one being very 
much smaller than any of the other eight. 
3. There is no perceptible difference between the chromosomes 
‘of £6 male and those of the female plant. 
5 BoLteter, E., Fegatella conica, eine morphologisch-physiologische Monographie. 
Beih. Bot. Centralbl. 18:327-408. 1905. 
6 WoopspuRN, W. L., Spermatogenesis in certain Hepaticae. Ann. Botany 
252299-313. 1911 
seca, A. M., The Socios of Concephalum conicum. Science, 
N. S. 532333. 1921. 
