1917] -  DUPLER—TAXUS CANADENSIS 123 
division between the microspore and the cells functioning in 
fertilization. 
Female gametophyte 
MEGASPORES.—STRASBURGER (2) long ago pointed out that in 
Taxus baccata the megaspore mother cells are the end cells of a 
series arising from the hypodermal layer of the nucellus, and that 
they are clearly distinguished from the surrounding cells by their 
larger size and larger nuclei. The same situation seems to hold for 
T. canadensis. STRASBURGER (2) claimed several megaspore 
mother cells; JAGER (6) agrees with him, but CoxKER (9) in his 
study of T. baccata states that there is no evidence that more 
than one megaspore is ever formed. He says ‘‘the mother cell is 
hard to distinguish. At the time of its first division it is long and > 
narrow, resembling very closely the cells adjoining.” As to the 
number of mother cells, STRASBURGER was probably right. In 
my preparations I have found no difficulty in recognizing the 
megaspore mother ‘cells, nor does there seem to be any doubt that 
there may be a number of them in an tee Only one, or occa-_ 
sionally two, may function, but other megaspore mother cells may 
be present, by all the other tests of a saatlies tt The mother cells — 
are distinguished from the other cells of the nucellus, not only by | 
their size and the size of their nuclei, but by their different staining 
reaction. The group of mother cells may be recognized in the 
autumn or winter (fig. 33). The occurrence of two linear tetrads _ 
of megaspores (fig. 38) is sufficient evidence that there have been at _ 
least two megaspore mother cells in the case figured. — 
STRASBURGER (12) and CoxEr (g) have given rather euiples : 
descriptions of megaspore formation in Taxus baccata, and the : 
Process is essentially the same in T. canadensis, so far as my prep- 
arations show (figs. 338). In r. saccola the second division a 
is said to he ci 
