Lemaneaceae of the United States. 197 
ripened their spores, till the following autumn, when the mat 
of rhizoids again puts out new protonemal filaments, on which 
new moss-stems arise.’ 
In the Characeae, on the other hand, the protonema is 
simple ; the rhizoids do not become changed into protonemal 
filaments but function as organs of attachment and for gaining 
nutriment. 
3. Development of the Sexual Shoot. The special lateral 
shoot of the Chantransia- form, which is the sexual shoot, 
arises either from the basal cells or at a variable height. It 
can at once be distinguished from a normal branch of the 
Chantransia- form by the greater transverse diameter of its 
cells and their shorter axis (Figs. 6, 10, 28, c\ The endo- 
chrome is darker in color, usually, in fresh specimens, and 
evenly distributed. The nucleus is usually very distinct. 
The cells are of two forms. The apical cell is convex at the 
distal end. In the subgenus Sacheria it is usually elongated 
in the direction of the longitudinal axis; in Lemanea it is quite 
short and shaped something like a ‘ half-moon.’ Figs. 6 and 7 
from L. ( Sacheria ) fncina , and Figs. 23, 28, and 29, from L. 
australis , represent the form of the apical and primary mother- 
cells. Each primary cell (Fig. 29 b) develops, by a process of 
centrifugal growth and peripheral and radial fission, into a per- 
fect sexual segment. As the proximal end of the sexual shoot is 
always imperfectly developed it will be necessary to study the 
growth of a cell some distance from the base. The course of 
development might be anticipated as follows. The primary 
cell develops a whorl of four perpendicular branches, the bases 
of which cover at first the entire peripheral surface of the axis. 
The central axis now elongates rapidly downward : each ray 
elongates perpendicularly to the axis at the same time that 
its outer end divides into 3 to 5 cells, as the case may be, 
outlining the beginnings of the ascending and descending 
generative filaments and the tie-cells of the ray. Terminal 
growth of the cells just outlined for the generative filaments 
takes place rapidly, and extends up and down parallel with 
the central axis to form other cells of the generative filaments, 
