458 BOTANICAL GAZETTE [JUNE 
(fig. 25). This method of division causes a radial appear- 
ance in a longitudinal section from the region of the embryo sac 
to the micropyle, which has been figured for Rosa hvida by 
Strasburger,> and occurs in other members of the rose family, 
such as Pirus Malus. There are variations in the number of 
megaspore mother-cells which enlarge for division. This number 
is usually one, but often two or three begin to divide, and then 
ont 2 SX 
oO 
- Longitudinal section of an ovule with integument, o 
Japonica, Longitudinal section of mature embryo sac normally 
cells in the chalazal region. X 550. ae 
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oa i 
Laos 
