Grinnellia americano , Harv . 15 
formed in the plane of the frond, growth begins in the third 
plane, producing a papilla-like thickening in these portions 
(Fig- 13)- 
The procarp consists of three cells and arises as a lateral 
branch from one of the large joint-cells in the plane of the 
frond (Fig. 14). In the haematoxylin preparations of mature 
procarpic cells it is found that each contains a well-defined 
nucleus within the densely granular, protoplasmic contents, 
and that these cells are connected by open pores which 
perforate their delicate cell-walls. The granular material 
passing through these pores gives a beaded, strand-like 
appearance to the protoplasmic connexion between adjacent 
procarpic cells. The basal procarpic cell is frequently the 
smallest in the branch and is connected with the supporting 
cell by a pore, and not by a pit as are the four contiguous 
thallus-cells which, with the supporting cell, form a charac- 
teristic group in the floor of the young cystocarp. 
It is possible that the early connexions between the cells of 
the procarpic branch were pits which became open pores by 
the absorption of the delicate cell-wall at the points of 
communication. 
The uppermost cell of the procarpic chain becomes the 
carpogonium from which the trichogyne develops (Fig. 14 tr). 
The trichogyne is subject to considerable variation. In some 
instances it is branched and much elongated (Fig. 17 b) ; in 
others it is simple, twisted, and of moderate length (Fig. 15). 
The granular protoplasmic contents of the trichogyne are in 
marked contrast to the clear gelatinous sheath enveloping it. 
Just above the carpogonium, a knee-shaped enlargement 
frequently occurs (Figs. 14 and 17 k). At this point the 
longitudinal axis of the trichogyne changes its direction and 
makes an angle of 30° to 40° with its former axis. This 
enlargement on one side of the basal region may be the 
cause of the changed direction of growth in the trichogyne, or 
may be an accompanying phenomenon due to the resistance 
which the young trichogyne must overcome when pressing 
between the cells of the rapidly-forming pericarp. 
