528 A BOTANICAL EXCURSION IN MY OFFICE. 
CEdogonium, has never been determined. In the allied 
genus Bulbocheeta, the resting spore finally breaks up 
into zoédspores, which grow into the plant 
in the same way as aber ZOOSpores. 
If we examine our filament closely, we 
will find it terminated by a long, exceed- 
ing delicate, bristle-like hyaline point, 
composed of cells whose walls are so deli- 
cate, as to be scarcely perceptible with 
very high powers, and at the end appa- 
rently consisting simply of primordial 
utricle, though I confess never to have ac- 
curately determined this by micro-chem- 
ical tests. Again, if we look at some 
{| of the large cells of the filament closely, 
Portionoffemateata. We Will find near their distal end one, 
oe Shana « two, three, or more streaks surrounding 
og mae ghowing> them like so many collars. Let us look 
still more closely. Why! such cells evidently have their 
wall beyond the first streak or line thickened, in fact bear 
on their upper ends little caps, as it were, the lines being 
in the caps. The causes of these two phenomena, the 
hyaline point and the little caps, are to be found in 
the peculiar methods of growth of the Œdogonia. The 
larger cells increase by a variety of cell multiplication by 
division. Cell multiplication by division is almost the 
_ only way in which all vegetable growth takes place. 
The process, as it ordinarily occurs, may be outlined in 
afew words. If a cell, about to undergo it, contains a 
nucleus, the first change takes place in that nucleus; 
a constriction can be. seen encircling and increasing in 
depth, until the nucleus is divided into two. When this 
: has taken place, a doubled reflection from the primordial 
La 
