94 BOTANICAL GAZETTE [AUGUST 
with spiral arrangement, with no definite perianth and often 
entirely naked, combined with the anemophilous habit, certainly 
indicate a condition somewhere near the beginning of flowering 
plants. The prominent leaf sheaths, which furnish protection 
and take the place of a perianth, are little modified from ordi- 
nary leaves, and the sporophores are without doubt cauline 
structures. 
DEVELOPMENT OF THE STAMENS. 
In the very young spike the beginnings of the stamen clus- 
ters appear as irregularly projecting outgrowths from the sides 
of the axis (figs. z, 2). These are of various shapes and sizes, 
depending upon the number of branches the future stamen 
cluster is to contain. Soon the branching begins to make its 
appearance by smaller wartlike processes developing on the 
primary projections from the axis. The separate stamens or 
branches attain quite a size before any difference can be 
detected in their cells to indicate the primary sporogenous cells 
(figs. 3, 4). Indeed, although one may feel sure that certain 
cells represent the primary sporogenous layer by their position, 
it would be quite arbitrary to draw any line and call some cells 
sporogenous and others not. After the stamen has increased 
somewhat in size, the sporogenous cells may be distinguished 
more readily by their position and size, although there is no 
apparent difference in their structure (fig. 5). At this stage 
several layers of cells are already differentiated in this way, and 
it appears that division may be going on both on the inner and 
outer parts of the sporogenous tissue (fg. 5). It was not pos- 
sible for me, with the stages at hand, to determine the origin of % 
the tapetum, and the layers of cells between the tapetum and 
the epidermis. When the stamen is in the early pollen mother 
cell stage the tapetum is already cut off, and between it and 
the endothecium is a single layer of cells (figs. 6,7). As the 
stamens with the sporangia enlarge, the tapetum begins to 
increase in size also, although it does not take on its glandular 
appearance until the pollen mother cells have separated (jigs. 9; 
