148. THE NATURE-STUDY OF PLANTS 
but, as already indicated, white petals are not of them- 
selves sufficient to justify separation as a variety but 
only as a form. 
Confining our attention for a moment longer to 
the Meadow Cranesbill, there are ten stamens in two 
rows of five apiece, and the pollination arrangements 
are as follows :— 
1. The inner stamens mature and shed their grains. 
2. The outer follow their example. 
3. After the exhaustion of all the stamens, but 
not before, the stigmas part company and become 
receptive. 
4. The petals fall and the stigmas dry up at the 
same time. 
This orderly sequence seems to be unvarying and 
to exclude, therefore, the possibility of spontaneous 
self-pollination. 
In the Storksbill things are very different. Its 
flower agrees with the Geraniums in possessing five 
petals, but the five antherless stamens do not of 
course count in pollination. 
T will deal with the corolla first, and then with the 
relative maturity of the anthers and stigmas. 
There is a good deal of variety in both the form 
and the duration of the petals: sometimes they are 
but little longer than the sepals, and sometimes all 
of them are twice as long. 
Again, two of them may be very small, and the 
other three much larger and longer, and either with 
or without a reddish spot. Occasionally one comes 
upon plants with white blossoms. 
The flowers open in the early morning and the 
petals fall by midday, or during the afternoon, or, 
at latest, the next day, recalling the Herb Robert. 
