189 
Lemaneaceae of the United States. 
development, the nucleus has divided, one part remaining in 
the spore, the other going into the germ-tube. Transverse 
fission soon takes place and a short oblong cell is formed. 
The germ-tube continues to elongate and produces a row of 
cells which soon branch as represented by the short cells at 
a , Fig. 4. Sometimes the germ-tube is proportionately 
more slender, as in Fig. 1, and grows more rapidly by 
extension in a longitudinal direction, producing confervoid 
elements of elongated narrow cells. The production of con- 
fervoid elements in the germination of the spores of the 
subgenus Sacheria is much less frequent than the develop- 
ment of the short cells represented in Fig. 4. It is quite 
probable that in some cases these confervoid elements may be 
quite numerous, but on reaching the substratum they soon 
develop the cellular form. 
Just the opposite condition of things obtains in the sub- 
genus Lemanea , where the confervoid elements predominate. 
There is a direct relationship between these facts and the 
nature of the prostrate form of the two subgenera. The short, 
polyhedral cells predominate in the subgenus Sacheria , and 
the confervoid elements in the subgenus Lemanea. Rarely 
the Chantransia-iovm may arise directly from the spore in the 
subgenus Sacheria about the same time that the germ-tube 
arises which produces the prostrate form. I have observed it 
in a few cases. In the subgenus Lemanea it is of quite 
common occurrence. In germination, the spore of this sub- 
genus may develop one or two germ-tubes. Where there are 
two from a single spore, they generally represent two different 
kinds of the elements which make up the protonema. One 
forms a confervoid filament, an element of the prostrate form. 
This is produced even when a germ-tube of another character 
is put out from the spore. The second kind of germ-tube is 
an element of the Chantransia-ioxm. While the second 
germ-tube is not so general as the first, it is quite common. 
It usually forms later than the confervoid germ-tube, after a 
few cells are developed, but it may precede it, as I have 
observed in quite a number of instances. 
