ANIMALS AND PLANTS 251 
plantain. A familiar case of proterandry is seen in the 
common scarlet geranium and other species of Pelargo- 
nium (Fig. 56, C, D). The stamens are ripe at the 
time the flower first opens, and the pollen is shed almost 
at once, but at this time the stigma is quite closed, and 
the stigmatic surface cannot receive pollen. In the 
older flowers, after the pollen is shed, the five lobes of 
the stigma spread out widely and the stigmatic sur- 
faces are exposed, but pollen must necessarily be brought 
from a.younger flower. 
A similar but more complicated arrangement is 
seen in the nasturtium (Fig. 56, E, F). Like Pelargo- 
nium there are seven stamens, which discharge their 
pollen before the stigma is in a receptive condition. 
The flower here is strongly zygomorphic, and the two 
lower petals are so placed as to form a resting-place for 
the bumblebees which are the commonest visitors to 
the flowers. In addition to this, two of the sepals are 
joined to form the long spur or nectary which the bee 
must probe for the honey contained at its apex. The 
seven stamens in a young flower are all bent downward 
(Fig. 56, E), but as they mature they rise, one by one, 
so that the open anther stands directly before the open- 
ing of the spur, and any insect seeking for honey must 
infallibly rub off some of the pollen. After all the 
stamens have discharged their pollen they turn down 
again, and their place is taken by the pistil, which has 
in the meantime elongated, and the three stigmatic 
lobes have opened and are ready to receive the pollen. 
The open stigma now occupies exactly the same position 
as did the open anthers, and any insect which has 
visited a younger flower is sure to deposit upon the 
