1903] GAMETOPHYTES AND EMBRYO OF TAXODIUM 3 
tissue, all the cells of the lower part of the sporophyll being of about 
the same size, and having dense contents. Soon, however, cer- 
tain centrally placed hypodermal cells begin to divide by peri- 
clinal walls and give rise to rows of cells as shown in fig. 7. 
The outermost cells of these rows, by a periclinal division, form 
the one-layered tapetum and the inner layer of the sporangial 
wall. By division of adjoining cells the tapetal layer is extended 
completely around the sporogenous tissue (fig. 2), and by Janu- 
ary, or earlier, the microspore mother-cells are formed and ready 
for their division in early spring. Chamberlain (’98) has reported 
a similar stage during winter in the microsporangia of Pinus, 
Cupressus, and Taxus. The cells of the whole sporophyll, with 
the exception of the tapetum and the sporogenous tissue, con- 
tain starch through the late fall and winter until renewed growth 
in spring alters its arrangement. In the middle of November 
the nuclei of the tapetal layer show a peculiar structure not 
found at other times. They havea very coarse and wide-meshed 
reticulum, upon which the chromatin is distributed in large 
granules of very unequal size. There is no nucleolus. The 
nuclei of the sporogenous tissue have several nucleoli and a 
thinner reticulum than at a later stage. 
No trace of an indusium-like outgrowth from the sporophyll 
is present for the protection of the sporangia, such as occurs in 
Cupressus, Thuja, and species of Juniperus. During early stages 
of development the cells of the upper part of the sporophyll are 
completely filled with a peculiar homogeneous substance staining 
bluish with gentian, which, as its subsequent history shows, is 
either a form of starch or an intermediate product in the forma- 
tion of starch. It is not stained blue by iodin. At the stage 
of fig. z, this substance is being replaced by starch grains of the 
usual kind, and a direct relation in amount between the two is 
evident, the starch appearing in proportion as the amorphous 
substance disappears. The cells on the line of transformation 
contain both starch and amorphous substances in proportionately 
smaller quantities. 
Before their division in the spring, the pollen mother-cells 
become filled with starch, while the grains in other parts of the 
