MODIFICATIONS OF ORGANS. 115 
Again, in other species, as if the pericarp itself were not 
sufficiently attractive, the seed is more or less enclosed in an 
aril, which is an appendage growing up from the funicle. 
This is well seen in the capsular fruit of the Kohe-kohe 
(Dysoxylum spectabile), which opens to display its seeds 
enclosed in bright scarlet coats. The spice known as Mace 
is the dried aril of the Nutmeg. 
Mechanical contrivances for scattering the seeds are not 
uncommon, but are not so conspicuous as the previous class. 
We are, however, familiar with elastic seed-pods in many 
plants—notably the Whin, or Gorse, and Broom. These may 
be heard cracking smartly on any dry sunny day in summer, 
and, if noticed, it will be seen that the seeds are ejected to 
a considerable distance. In Balsam (Jmpatiens) the capsule 
becomes very elastic inside, and when ripe cracks up along all 
its five valves at once with a peculiar twisting movement. 
In Woodsorrels and Shamrock (Oxalis) the seeds are enclosed 
in elastic membranes, which rupture when touched, and thus 
throw the seed a distance of several feet. 
All these numerous contrivances serve the same end—viz., 
the distribution of the seed, by which the chances of the 
species to survive in the intense struggle for existence always 
going on are greatly increased. 
