SPORE-PRODUCING MEMBERS 417 
abaxial loculus which will be thus traversed. A truly radial section of a 
young synangium is shown in Fig. 232 3, the arrow indicating the direc- 
tion of the main axis: the cell (x) is a conical cell, which is commonly 
though perhaps not constantly found occupying the centre of the apical 
surface of the synangium. The cell shaded is believed to be the arche- 
sporial cell for one of the loculi, but after comparison of a large number 
Fic. 232. 
Psilotum triguetrum, Sw. Various stages of development of the synangium and 
sporangium. In C the sporogenous group is shaded. D shows the differentiation of its 
cells, the fertile cells being shaded. £ shows the disorganisation of the remaining cells - 
without forming spores. X roo. 
of séctions I am still uncertain whether the whole of the sporogenous tissue 
in each loculus is really referable to a single parent cell, for just the same 
difficulty arises here as in Zmesipieris in recognising the exact limits of 
the sporogenous masses. 
The subsequent stages of development are illustrated by Figs. 232 C, D, E, 
and it will be seen from these how the sporogenous masses assume large 
dimensions, and are at first composed of uniform cells. The wall of the 
synangium meanwhile becomes multiseriate, and the cells of the outermost 
layer assume a deep and prismatic form, while the inner layers are narrow. 
2D 
