Nichols, A morphological study of Juniperus communis var. depressa. 229 
living egg nucleus in Dioon, writes that his results are far from 
satisfactory, that “anucleolus is visible, but otherwise the contents 
are nearly homogeneous. There are few globules and the network 
could not be identified". He adds: “It is possible tbat most 
of tbe globales and tbe network are coagulation products due to 
fixing”. 
Maturation of tbe egg nucleus. — Tbe egg nucleus 
grows rapidly, usually becoming sligbtly ovoid in sbape, and sbortly 
bef'ore fertilization bas acquired a length of about 40 pi. Figs. 86 
and 87 sbow two of tbe various aspects wbicb it presents during 
its development, wbile fig. 92 represents tbe mature oospbere 
nucleus. At tbe time of fertilization tbe reticulum appears as a 
network of almost colorless, granulär threads wbicb ramify through- 
out tbe nucleus and exbibit slight indications of a differentiation 
into chromatin and linin, wbile sometimes tbere is also visible in 
tbe nuclear cavity a faint protoplasmic mesbwork (fig. 87). Coin- 
cident witb tbe growtb of tbe egg nucleus tbe vacuole of tbe egg 
cell diminishes in size (figs. 91, 95). 
Fertilization. — Fertilization stages were found in material 
collected June 15 th , 1906 and June 29 th , 1907. In 1908 daily 
collections from June 6 th to 13 th sbowed tbat, altbougb fusion is 
almost simultaneous in all tbe arcbegonia of a single ovule, a week 
or more may elapse between conjugation in different flowers on 
tbe same plant. In material collected June 7 th , for example, tbe 
body cell in many pollen tubes bad not yet divided, wbile in 
other cases fertilization bad taken place and tbe development of 
tbe proembryo bad begun. 
Preparatory to fertilization tbe membrane of tbe pollen tube 
is dissolved or ruptured directly above tbe neck of an arcbegonium, 
and one of tbe male cells squeezes tbrougb tbe neck into tbe egg, 
carrying tbe broken-down neck cells witb it. Tbere is no receptive 
vacuole in tbe oospbere, such as occurs in tbe Ahieteae. Tbe 
wall of tbe male cell is cäst off during its entrance into tbe egg, 
or immediately afterward, and is frequently seen lying eitber Out¬ 
side tbe neck or, togetber witb tbe disorganized remains of tbe 
neck cells and vegetative nuclei of the male gametopbyte, in tbe 
upper part of tbe egg. Reference bas already been made to tbe 
equality in tbe size of tbe male cells, and ample proof bas been 
found tbat both may be functional. Numerous cases were noted 
where tbe number of developing proembryos is greater tban tbat 
of tbe pollen tubes present, wbile fig. 95 sbows one instance where 
two male cells from tbe same pollen tube (tbe only pollen tube 
present in Jbis ovule) are in tbe act of entering different arcbe¬ 
gonia. In tbe event of more tban one male cell entering tbe 
same arcbegonium only one functions, tbe superfluous cell disinte- 
grating in tbe upper part of tbe egg cell. 
Tbe male nucleus, accompanied or followed by its mantle of 
cytoplasm and starch, rapidly approaches tbe female nucleus wbicb 
has come to lie sligbtly above tbe center of tbe egg. Figs. 
96—101 illustrate tbe general appearance of tbe conjugating nuclei, 
