1032 Means of Plant Dispersion. [October, 
and in the elastic movement project the seed with force. The 
valves of the pods of violets also fold together when ripe, and 
throw out the seeds attached to the middle part of them. Ha 
mamelis, or witch-hazel, is even more remarkable; the fruit isa 
two-celled, woody pod, opening at the top. Each cell usually 
contains but a single bony seed. When mature the outer coat of 
the cell separates from the inner, which encloses the seed. This, 
pressing the seed as it bursts elastically from the top, often throws 
it several feet as it escapes from the pressure, like a boy shooting 
a pea or bean by pressing it between the two parts of a split stick. 
These movements are generally due to the unequal tension of 
cells on the outer and inner sides of the walls, causing a rapid 
warping together in the direction of the greatest strain, and arè 
similar to many other plant movements, like the bursting of the ; 
anthers in the barberry.} | yy, 
It will be seen from what has been brought to notice that a 
great many kinds of plants are provided with means of disper- 
sion, and that we can find genera and species in a large number of 
families that furnish examples of special contrivances. No effort 
has been made to be exhaustive in the treatment of the subject, 
even for our own flora, as it has not received sufficient attentiog’ 
to admit of this. But that the greater part of plants qan aval 
themselves of some agency, either in themselves or their 
roundings, or both, seems very evident; it may be said, we: ce 
admits of doubt. It is in accordance with the great plan of nature : 
that all shall be cared for. ; Bee 
Nothing has been said about the indirect aid furnished by = l 
any further than that of any animal. I have frequently been entet 
pare 
tained, even if annoyed, while collecting plants, by ani on 
contribution to this work. With clothes well covered with 
and other adhesive fruits, the lesson has been learned ai ge 
let them alone, not picking them off one by one, but lea 
them to be brushed off in neighboring clumps of buses 
patches of grass that may soon be the place of search, yi 
most will disappear and be left to propagate their kind. At aay 
times of the year a day’s work in gathering is also a 
in dispersing. The indirect scattering of seeds by raiti a 
1 Mr. J. C. Arthur, of Charles City, Iowa, being present at the reading d 
paper, and engaging in the discussion that followed, stated that he wast 
species of Euphorbia projecting their seeds with force from their pods. z 
