BY THE PRESIDENT. 
15 
escaped from their capsules. The u shells” of walnuts have a 
disagreeable flavour, and so have the pips of the orange, while the 
pips of the apple not only have the usual power of the seeds of 
brilliant-coloured fruit of resisting digestive fluids, but they also 
are surrounded by a core. Many of the capsules of plants when 
ripe explode and scatter the seeds, as in the balsams. According 
to 'Wallace,* plants whose seeds are ejected by the bursting open of 
their capsules, as with the Oxalis and many of the Caryophyllacese 
and Scrophulariaceae, etc., have their seeds very small and are 
rarely or never edible. Dried fruits and naked seeds can remain 
in salt-water for a considerable time with uninjured vitality, 
and can therefore be conveyed by the sea to distant shores where 
they may he removed by birds to the interior and there germinate. 
Prickly capsules are not only a means of protection but also of 
dissemination, on account of their liability to become attached to 
the hairy skin of animals. 
I have already referred to the care some plants take of their 
seed, hut one of the most interesting means of protection is the 
power some seeds possess of burying themselves. The beautiful 
feathers of the feather-grass (Stipa pumata ) are the awns of the 
seed of the plant. As the awn becomes alternately damp and dry, 
so its feathery portion revolves, hut if this movement be prevented, 
the seed will revolve. Now, when the seed is dropped, it remains 
in a vertical position, so that it rests on the ground with its point 
downwards, or if it should fall among vegetation it will be caught 
by its feather. Many seeds would thus be brought in contact with 
the earth, and twisted into the earth. The arrested revolutions of 
the feathery portion do not, however, entirely explain the burial 
of the seed, for the direction of the rotatory motion of the 
seed is changed, according as the feather is wet or dry. This is 
apparently successfully prevented by some small hairs on the seed 
which point upwards and resist the traction. Francis Darwin 
states that in one experiment “ in three wettings and three dryings 
28 mm. was buried in the sand. In another experiment a seed 
16 mm. was completely buried in three wettings and three 
dryings.” f The same process is seen in the oats, geraniums, and 
many other plants. 
The spores of the Equiseta are specially adapted for falling in 
places suitable for their development. Each spore has two pairs of 
elastic filaments which are extended when dry, hut close together 
even with the moisture of the breath. It can scarcely he imagined 
* Idem., p. 227. 
t ‘ Trans. Linnean Soc.,’ 2nd series, Botany, vol. i, p. 155. 
