6 
Elizabeth Acton. 
under the necessary conditions and producing new plants. They 
occurred fairly frequently in the material which I examined and 
seemed always to have very dense crowded contents and a 
thickened cell wall as described by Kjellman for his “ basal gonidia.” 
Fig. 4 shows one of these old cells putting out new branches. 
In addition to these old axial cells, structures were present 
which undoubtedly have a definite reproductive significance. 
These are of the nature of hypnospores, and as far as I am aware, 
have not been mentioned elsewhere. These resting spores when 
mature may reach a diameter of 120/x though many are smaller. 
They are almost spherical in shape and have very thick walls. The 
cell contents are densely crowded and contain a large quantity of 
oil (Fig. 5). 
Fig. 4. Old cell from main axis which has become isolated and developed 
new branches, x 96. 
It is probable that the contents of a single large vegetative 
cell break up into numerous resting spores though this has not 
actually been seen. The spores frequently occur in groups as in 
Fig. 5, A. The spores in such a group vary in diameter from 16/x 
to 46yx and have possibly just been liberated. Larger spores were 
generally isolated or in groups of two or three, as in Fig. 5, B. In 
many cases single spores were formed in the narrow cells of the 
“ rhizoids ” and “ cirrhoids ” and were seen escaping from the old 
cell. The narrow filament swells considerably in places and the 
protoplast concentrates at these points. Fig. 3, B, shows what is 
probably an early stage in the formation of resting spores from a 
“ cirrhoid ” branch. 
On germination the outer coat of the spore is ruptured and is 
either completely thrown off as in Fig. 5, E, or remains for some 
time attached to the spore as in Fig. 5, D, F. The first stage in 
germination is a definitely marked thickening, similar to that which 
appears when a vegetative shoot is about to develop a branch at 
