364 
FOUNDATIONS OF BOTANY 
which are unripe, shut together, and tucked aside out of | 
reach. On flying to a flower in the later stage the pollen 
just acquired will be lodged on the prominent stigmas and 
thus produce the desired cross-pollination. 
Fic. 256. — Provisions for Cross-Pollination in the High Mallow. 
I, essential organs as found in the bud; IJ, same in the staminate stage, the 
anthers discharging pollen, pistils immature; III, intermediate stage, 
stig, the united stigmas; IV, pistillate stage, the stigmas separated, 
stamens withered. 
Closely related flowers often differ in their plan of 
pollination. The high mallow, a plant cultivated for its 
purplish flowers, which has run wild to some extent, is 
admirably adapted to secure cross-pollination, since when 
[ 
Fie. 257.—Stamens 
and Pistils of Round- 
Leafed Mallow. The 
stigmas curled round 
among the stamens 
to admit of self-pol- 
lination. 
its stamens are shedding pollen, as in 
Fig. 256, II, the pistils are incapable of 
receiving it, while when the pistils are 
mature, as at IV, the stamens are quite 
withered. In the common low mallow 
of our dooryards and waysides insect 
pollination may occur, but if it does not 
the curling stigmas finally come in con- 
tact with the projecting stamens and 
receive pollen from them, as is indicated 
in Fig. 257. 
