244 BOTANICAL GAZETTE [ocTOBER 
forms most of the embryo, while the micropylar one gives rise to the 
suspensor and a small part of the young embryo. The second division 
( fig. 8, wall 2) is in the micropylar cell and is also transverse; the third 
division (jig. 8, wall 3) is in the chalazal cell and is longitudinal. 
Divisions continue in the descendants of the micropylar cell until a 
row of about eight cells is formed (fig. ro). The seven of these which 
are nearest the micropyle make 
up the suspensor, while later 
on the other one divides to 
form part of the embryo ( fig. 
11). The first division in this 
cell may be either transverse or 
longitudinal. When the row of 
cells derived from the primary 
micropylar cell has become 
four or more cells long, trans- 
verse segmentation begins 12 
the descendants of the chalazal 
cell (fig. 9), so that this be- 
comes cut into quadrants (Jig: 
Fic. 11. Still older embryo drawn on a ro). Up to this stage the 
smaller scale; the suspensor has elongated. have 
, sor 
—Fic. 12. Many-celled embryo. embryo and suspen 
- remained within the embryo 
sac Cavity, but now the cells of the suspensor elongate and the free 
end of the suspensor is pushed through the micropyle out beyond the 
integuments (cf. shape of cells in figs. ro and 11). The cells of the 
embryo undergo further division and form a globular mass; fig: - 
represents a young embryo in which walls 1 and 3 correspond to 1 an 
3 of figs. 8-11. 
Discussion 
MEGASPORES 
In Habenaria the megaspore mother cell divides to two eet 
cells and each of these divides to two megaspores. The nee” 
the daughter cell nearest the micropyle is usually delayed until wai 
that in the daughter cell nearest the chalazal end. If this delay ae | 
carried a little farther, we should have the condition described 
