273 
Hybridization and Crossbreeding 
may be dusted on the stigma two or even three times on 
successive days, if needs be, to ensure it taking properly. 
It is no guide, either, to say that the stigma will be ready 
when the anthers are matured on flowers of the same age, 
the anthers, of course, having been cut out of the flowers 
you wish to pollin- 
ate, to prevent self- 
pollinization. Some- 
times the anthers 
are matured before 
the stigma in the 
same flower — pro- 
terandrous. This is 
the case in plants 
belonging to the 
Umbelliferae, Com- 
posite, and Cam- 
panulaceae orders. 
In other cases the 
stigma is matured 
before the anthers 
Section of Style of Lilium Martagon, showing Pollen-cells 
ptOtOgy nOUS aS on t ^ e s t jg ma> anc j sending down their Tubes along the 
in Plantains, Arums, Conducting Tissue of the Style 
and Aristolochia. 
When pollination has been effected, with both the pollen 
and stigma in the proper condition, the pollen grains ger- 
minate, and send out a little tube (the pollen tube). This 
grows right down through the tissue of the stigma and 
style until it reaches the ovary. It then makes its way 
to the small opening in the ovule — the micropyle — through 
which it enters into the embryo sac. It is then guided 
<C525) 19 
