Embryo of Sequoia semper virens. 
9 
The Female Gametophyte. 
Shaw (1896) has given an accurate account of the development of the 
macrosporangium and the integument, but has, however, given a very 
meagre description of the sporogenous cells and the macrospores. There 
may be as many as five or six macrospore mother-cells organized from the 
hypodermal cells of the sporangium. Many preparations were made of 
this stage in the development of the sporangium, and a special study was 
made of the mother-cells as soon as they became differentiated from the 
surrounding sterile cells. They first become recognized as mother-cells 
by their large deeply staining nuclei. In the beginning they are not much 
larger than the other hypodermal cells, but they very soon enlarge, and 
their cytoplasm becomes very dense and granular and stains very readily 
with orange G. They are further characterized by the absence of large 
vacuoles. They are situated just about the centre of the sporangium ; 
about five or six layers of cells lying between the uppermost of them and 
the epidermis at the apex. A careful study was made of the number of 
mother-cells formed, and there seems to be a slight variation in this respect. 
Six was the largest number found. In all the sporangia studied five or six 
was the prevailing number, but in no case were fewer than four found. 
Shaw (1895) has reported that these sporogenous cells divide twice, each 
cell giving rise to four spores. As there are nearly always five or six of 
these sporogenous cells developed, and if each one gave rise to four spores, 
this would result in the formation of twenty or twenty-four macrospores. 
We shall show later that no such large number of macrospores were formed, 
but that, on the contrary, ten or twelve were the prevailing numbers met 
with. Owing to Shaw’s statement, it was thought probable that some of 
the sporogenous cells had failed to divide and that others had divided 
twice. Accordingly a very vigorous search was made for the stages 
showing a second division. Although the spindles of the first division were 
found frequently, some with the chromosomes at the equator of the spindle 
(Fig. 10), and others with the daughter-nuclei formed, in no case was there 
any evidence of four spores having been formed from a single mother-cell. 
From these observations I feel tolerably certain that the five or six sporo- 
genous cells (Fig. 9) differentiated from the hypodermal cells of the 
sporangium are the macrospore mother-cells, and after dividing twice give 
rise to the ten or twelve macrospores ; one cell of the second division 
fails to develop. 
Soon after their organization, about the first of March, the mother-cells 
divide, each producing two macrospores. As this division of the mother- 
cell is the reduction-division, which marks the beginning of the gametophyte, 
the character and number of the chromosomes demanded considerable 
attention. As far as the writer is aware, the reduction of the chromosomes 
