
ON EMBRYONIC FISSION IN PLANTS. 97 
adult Adogonwm. In Coleocheta fertilization is effected 
as in Afdogonium, but the cells into which the embryo 
segments remain united and form a cellular mass, which 
is generally considered as a parasitic sporophyte.* The 
parenchymatous mass of cells, however, which results 
from the segmentation of the embryo of Coleocheta, after 
a time bursts from its capsule, formed by a filamentous 
_ outgrowth from the parent plant, and each cell by 
rejuvenescence gives rise to a motile cell, which is capable 
of producing on germination a sporophyte.t 
I fail entirely to see wherein the difference between the 
life-histories of Aidogoniwm and Coleocheta lies, save that 
in the latter the formation of the motile cells is postponed. 
The parenchymatous mass formed by segmentation of the 
embryo of Coleocheta is, in my opinion, in no sense an 
individual, any more than the collection of motile cells 
which originates from the embryo of Hdogonium is an 
individual. In the case of Hdogcnium embryonic fission 
has taken place, by means of which the number of embryos 
has been greatly increased. That these are motile is 
easily accounted for by the aquatic habit of the plant, and 
by the fact that the life-cycle is usually completed in one 
season. If germination commences in the following spring 
the oospore rests during winter protected by a thick and 
often spiny cell-wall. In Coleocheta, on the other hand, 
we have to deal with a plant living in stagnant water and 
usually attached to the submerged parts of plants where 
manifestly the possibilities of diffusion are not so great, 
and moreover, incapable of completing its life-cycle in one 
season. The embryos, or products of embryonic fission, 
* On the Alternation of Generation in the Thallophyta. Prof. S. H. Vines. 
Journal of Botany, Noy., 1879. 
+ Outlines of the Classification and Special Morphology of Plants. Goebel. 
p. 47. 
