69 
Geological Survey Branch of the Canada Department of Mines. 
Attention was especially called to the puzzling arrangement of 
the text, the innumerable errors of typography and punctuation 
and the peculiar methods adopted throughout for citation and 
nomenclature 
Mr. C. A. Darling presented a paper on ‘Sex in Dioecious 
Plants,” those plants in which the male and female flowers are 
borne on joel individuals. Heredity, the transmission of 
characters from a to offspring, is one of the fundamental 
problems ~ biolo The determination of sex as now view 
ae be considered a Ge onet of heredity. » Until within the 
last few years it was generally believed that sex was determined 
in large measure, at least, by external factors ; however, more 
recent observations and experiments tend to show that sex in 
strictly dioecious forms is not determined by surrounding condi- 
tions, but that it is predetermined in the germ cells. € ex- 
cellent work of the Marchals upon dioecious mosses has shown 
that in the nates cases . the moss two kinds of spores are formed ; 
pon mination, half of the spores will produce only Bale 
as me half only ee plants. Correns working upon some 
of the dioecious flowering plants has found that two kinds of 
pollen spores exist; one half of the spores possessing the male 
tendency, the other half the female tendency. Noll has indepen- 
dently arrived at the same conclusion in his work upon dioecious 
hemp 
So far as is known, up to this time nothing has been published 
on the behavior of the chromatin (one of the microscopic ele- 
ments of the plant cell) in dioecious plants. In working upon 
the formation of the pollen-spores in box-elder (Acer Negunde) 
which is strictly dioecious two kinds of chromosomes (bodies 
which result from the separation of A chromatin into a definite 
number of parts) are found which are formed in different ways. 
Considering all that has been done upon dioecious plants it seems 
probable that there is a separation of the two sets of sex charac- 
ters in the formation of the spores in mosses; and that in dioe- 
cious flowering plants the spore-bearing plant normally contains 
both sex characters but that one set is latent while the other is 
