Lemaneaceae of the United States. 187 
layer by pyriform or boot-shaped cells, one on each side 
placed near the ends. The generative filaments are also 
closely applied to the wall throughout their entire length. In 
each sexual segment there are four descending filaments, 
corresponding to the descending ends of the ray-cells ; and 
six ascending, alternate ascending ends of the ray-cells 
branching and forming two ascending generative filaments. 
Near the antherid-zone the cells are shorter and greater in 
diameter. Here they also branch, and the terminal cells of the 
branches are distributed to the bases of the papillae. See 
Figs. 11 and 12 for arrangement of generative filaments and 
shape of the cells. 
In the subgenus Lemanea the central axis is at first naked, 
but later becomes entirely covered by slender filaments, which 
arise from the proximal ends of the ray-cells and spirally 
surround it (see Fig. 32). The ray-cells do not reach the 
medullary layer of the wall. They are simple cells, usually 
clavate, the smaller end joined to the central axis. The distal 
end is not applied to the wall, but is supported by another clavate 
or pyriform cell. The shape and relations of the ray-cell and 
tie-cell can well be seen in Fig. 32. These tie-cells are connected 
where they meet with the medullary layer, by three or four 
pyriform cells. The generative filaments arise from the 
distal ends of the ray-cells, and are also separate from the 
wall, being supported by pyriform tie-cells, except at the 
antherid-zone, where they come in contact with the wall. In 
their disposition they exceed in number those of the subgenus 
Sacheria. Two oppositely situated ray-cells give rise each to 
four generative filaments, two ascending and two descending. 
One of the ascending generative filaments nearly always 
branches after the first cell, making three ascending filaments 
for two ray-cells. The other two oppositely situated ray- 
cells bear each three generative filaments, one ascending and 
two descending. Thus at the point of origin of the generative 
filaments from the ray-cells there are six ascending and eight 
descending, the ascending becoming eight by the branching 
of two of the first cells. 
