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THE POPULAR SCIENCE MONTHLY. 



the sweet violet attempted to shoot its seeds, the capsules not being 

 sufficiently elevated, the seeds would merely strike against some neigh- 

 boring leaf, and immediately fall to the ground. Hence, I think, we 

 see that the arrangement of the capsule in each species is that most 

 suitable to the general habit of the plant. 



In the true geraniums again, as for instance in the herb-robert 

 (Fig. 6), after the flower has faded, the central axis gradually elon- 

 gates (Fig. 6, c, d). The seeds, five in number, are situated at the 

 base of the column, each being inclosed in a capsule, which terminates 

 upward in a rod -like portion, which at first forms part of the central 

 axis, but gradually detaches itself. When the seeds are ripe the ovary 

 raises itself into an upright position (Fig. 6, e) ; the outer layers of 

 the rod-like termination of the seed-capsule come to be in a state of 

 great tension, and eventually detach the rod with a jerk, and thus 

 throw the seed some little distance. Fig. 6, /", represents the central 

 rod after the seeds have been thrown. In some species, as for instance 

 in Geranium dissectum, Fig. 7, the capsule-rod remains attached to 

 the central column, and the seed only is ejected. 



It will, however, be remembered that the capsule is, as already 

 observed, a leaf folded on itself, with the edges inward, and in fact 

 in the geranium the seed-chamber opens on its inner side. You 



Diagram. Fio. 7. Geranium dissectum. a, just before throwici? seed; b, just after throwing 

 seed ; c, the capsule still attached to the rod ; d, the seed. 



will, therefore, naturally observe to me that, when the carpel bursts 

 outward, the only effect would be that the seed would be forced 

 against the outer wall of the carpel, and that it would not be ejected, 

 because the opening is not on the outer but on the inner side. Your 

 remark is perfectly just, but the difficulty has been foreseen by our 



