Geraniums . 133 
normal or daylight position. A slight concussion 
on the leaf-stalks will produce effects similar to 
darkness. 
The flower of Wood Sorrel is very similar to that 
of Herb-Robert. The erect sepals produce a modified 
tubular effect in the lower part of the corolla, which 
is helped by the petals cohering above the “claws.” 
The petals are white, delicately marked with purplish 
honey-guides. The five carpels are united to an axis, 
but the styles are free, and their tips only are 
stigmatic. The flower is designed for insect-fertilisa- 
tion, but no doubt often does without, for the flowers 
are like the leaves in that they close up at night, and 
then the stigmas are almost certain to get pollen 
attached. But in addition to these showy flowers 
displayed in spring, the Wood Sorrel produces never- 
opening (cleistogamous) flowers like those of the 
Violet, already described, only in this case these are 
little twisted petals which remain unexpanded until 
the swelling of the seed-capsule throws them off like 
a little cup. Within these cleistogamous flowers only 
five of the stamens produce pollen, and these are 
attached by hairs to the summit of the ovary close 
to the exceedingly short styles. 
No matter by which kind of flower the seed-vessel 
is formed, it is altogether different from those of the 
Crane’s-bills and Stork’s-bills. The carpels remain 
attached to the axis, and each contains two or three 
seeds of a flattened rugged character, and red in 
colour. Each seed is wrapped in a white envelope, 
which is brought up to the opening of the ripe carpel, 
and if the plant is touched, or the pot it 1s growing 
in is jarred, the seeds are ejected with great force 
