MLE i 2 re re rrr a ane eee ee Ee 
r i roe ee 
1904] LAND—EPHEDRA TRIFURCA 13 
The nucleus of the central cell lies in close proximity to the neck 
of the archegonium. As the central cell enlarges, it does not have 
a conspicuous vacuole in the center, like Pinus and the Cupressineae, 
but is almost completely filled with cytoplasm except in the immedi- 
ate vicinity of the nucleus, where there are a few small vacuoles. 
Later the cytoplasm in the lower part of the archegonium becomes 
almost homogeneous. A conspicuous kinoplasmic mass lies at a 
little distance below the nucleus (fig. gz). In the earliest stages it 
is coarsely granular, and later becomes dense, and is larger and 
sharper in outline than the similar body which is so conspicuous in 
some of the pines and in Thuja occidentalis. 
When two or three archegonia are present, one is usually smaller 
than the others, as is shown in fig. 38 (a cross-section through the 
middle region of the archegonia). When one archegonium is present 
it is very large as compared with the larger of two in a gametophyte. 
It is questionable if the eggs in the smaller archegonia regularly 
function. 
The jacket-cells are at first rectangular, with the longer axis at 
right angles to the long axis of the central cell (fig. go). Since peri- 
clinal division does not keep pace with the elongation of the central 
cell, the jacket-cells become much elongated (fig. 41). Their walls, 
never at any time thick, become so tenuous that they can scarcely 
be seen, and evidently offer little resistance to the passage of food 
into the central cell. There is evidence that at the time of fertiliza- 
tion the walls separating them from the egg break down altogether. 
Fig. 41 shows two archegonia at the time of pollination (April 15, 
1903). 
The ventral nucleus was cut off about April 15 in the season of 
1903. In material collected during the season of 1904 from the 
same plants, the ventral nucleus was cut off about April 1. This 
difference is probably due to the fact that the season of 1904 was 
unprecedentedly hot and dry. 
No trace of a wall can be seen between the ventral nucleus and the 
egg, although in some instances there is a suggestion of cytoplasmic 
thickening between the two nuclei. The cytoplasm at the upper end 
of the central cell is still quite vacuolate; in the lower part it has now 
become very dense, in fact almost homogeneous. 
