212 BOTANICAL GAZETTE [SEPTEMBER 
well; later the irregular thickening bands appear in its cells 
(fig. 5). 
The filaments do not begin to elongate until March 20, when they 
extend quite rapidly, the microsporangium being fully mature 
March 26. 
MEGASPORANGIUM. 
On February 13 the megasporangium consisted of the nucellus 
containing a single hypodermal archesporial cell and a single integu- 
ment. The archesporial cell divides by a periclinal wall, and the 
outer daughter cell also divides by a periclinal wall, giving rise to 
two parietal layers of cells (fig. 23); one of these occasionally again 
divides. The megasporangium evidently passes the winter in the 
megaspore mother cell stage, thus being identical in this particular 
with the microsporangium. 
By February 15 the mother cell begins to enlarge. It accom- 
plishes this chiefly by elongation, the long embryo sac pushing its 
somewhat pointed lower extremity deep into the tissue of the nucellus 
(fig. 24). The second integument appears February 25. By March 
15 the first integument has closed over the top of the nucellus (jig. 
27), whose crown cells have already begun to enlarge and divide pre- 
paratory to forming the long beak-like or archegonium-like necks 
shown in figures of more mature stages. These archegonium-like 
necks strongly resemble those figured by Miss Lyon (15) for Euphor- 
bia corollata, They differ however from those of Euphorbia in that 
they do not project through or beyond the integuments, but press 
against them. Possibly the rapid anticlinal divisions of the cells of 
the inner integument cause the elevation, thus forming a dome-like 
cavity into which the beak-like tip of the nucellus grows (figs. 27-35): 
The integuments are fully developed by March 25. A third integu- 
ment was clearly made out in a number of instances (fig. 27), which 
1s probably due to the splitting of the outer integument. 
MALE GAMETOPHYTE. 
The mother cells were found in the first and second mitosis sa 
February 15 (jigs. 6-7). About February 25 there appears 4 a 
tinct though delicate wall about each of the four young spores, whi 
are still enclosed by the wall of the mother cell (fig. 9)- The wall 
