SPERMATOPHYTES 
223 
a very prolonged process. Probably in no case is the period between the 
first appearance of the ovule and the shedding of the seed less than two 
growing seasons; and in some cases the seed is not shed until the third 
season after the ovule appears, pollination taking place during the second 
season. 
Female gametophyte. The development of the female gametophyte 
proceeds as in the previous groups, until an extensive endosperm is 
formed. At least two distinct regions of the endosperm are always evi- 
dent; namely, a region of smaller 
cells towards the micropyle, in 
which the archegonia develop, and 
a deeper region of larger cells, 
which functions as a nutritive 
region. 
Archegonia. The archegonia 
range in number from one to sixty, 
the usual numbers among the 
Abietineae being three to five. In 
the Taxodineae and Cupressineae 
an archegonium complex is organ- 
ized; that is, a group of archegonia 
is invested by a common arche- 
gonial jacket and has a common 
archegonial chamber (figs. 491, 
492). The necks of the archegonia 
are remarkably variable in the *"S two neck cells the central cell 
, . .. . (whose nucleus is just about to divide to 
number of Cells, ranging from the form ventral canal and egg nuclei), and the 
ordinary two-celled neck to that archegonial jacket. After COULTER and 
in Pinus, which consists usually CHAMBERLAIN - 
of two tiers with four cells in each tier, but may reach four tiers with 
as many as sixteen cells in each tier. In the Abietineae a definite 
ventral canal cell is formed (fig. 493), but in Taxodineae and Cupres- 
sineae only a ventral nucleus appears (as inTaxaceae); while in Arau- 
carineae the situation is unknown. 
Male gametophyte. The male gametophyte is quite variable as to 
the number of vegetative (prothallial) cells, but the condition is usually 
constant in each tribe. In Abietineae there are two vegetative cells, 
both of which are ephemeral (figs. 494-500) ; in Taxodineae and Cu- 
pressineae there are no vegetative cells (as in taxads); while in Arau- 
FlG - 493- Archegonium of Pinus, 
