108 JOUKXAL OF THE KOYAL HOETICULTUEAL SOCIETY, 
effectually dispersed without any expressly facilitative adaptations. Such 
are the recorded cases of mud adhering to the webbed feet or feathers of 
migratory waterfowl, or the mere washing of soil, with its contained 
seeds, down a hillside in time of flood. 
Even when we come to examine most effective adaptations for the 
dispersal of fruits and seeds, we may perhaps convince ourselves that the 
most successful are, as Kerner has urged, not too highly specialised, but 
may serve either for dispersal by wind, water, or animal agency. It has 
been usual of late years to classify dispersal-mechanisms under four heads, 
viz. (1) ejection by the plant ; (2) transport by water, (3) by air, or 
(4) by animals. Though it is true that, in the initial stages of adap- 
tation, there is less modification in the first of these groups than in 
the others, there are, higher up in the series, so many elaborate con- 
trivances that I prefer to take the case of water-borne fruits and seeds 
first, as being the simplest of the four cases throughout. 
Mere lightness of seeds or fruit would seem to be more often an adap- 
tation to wind transport than to water carriage, the most noteworthy 
cases being those of epiphytic Orchids, parasites, and saprophytes on the 
one hand, and steppe plants on the other. There is, however, a class of 
cases in which small seeds, readily carried by runnels of rain-water, seem 
to be of special utility, viz. plants living in stony, arid, or almost soil- 
less situations, clinging with difiiculty to vertical faces of rock, and liable, 
if not carried into crannies, to be speedily killed by drought. Such is 
the case of the Stonecrop (Scclum acre, L.), in which the five follicles- 
remain closed in dry weather, but burst when a drop of rain falls into the 
shallow basin-shaped hollow at the top of the fruit. The Ivy-leaved Toad- 
flax {Linaria Cymhalaria) has small seeds which may be similarly 
washed into crevices. So, too, the capsules of the South African: 
species of ^lesemhryantliemum only open when moistened. In the genus- 
Veronica we have slightly different arrangements in different species 
according to their habitat. V. serpyllifolia and others living in dry 
places have capsules which open when wetted, as in Sedum acre ; whilst 
V. Beccahunga and V. AnagaUis, though they may crack their capsules 
on ripening, do not open fully until thoroughly wetted, when the seeds- 
become mucilaginous, like those of the Flax, and stick to the ground 
unless washed away by a strong current. With regard to another adap- 
tation for water carriage, which figures largely in books, viz. the power 
of withstanding long immersion in fresh or salt water, I should like to 
suggest that this power may in some cases be otherwise acquired, may in 
fact be an adaptation to quite distinct purposes, the resistent pericarp or 
testa being perhaps initially a protection against the gastric juices of 
animals, or against the moisture and warmth which might bring about 
premature germination on land, rather than against prolonged sub- 
mergence. When, for instance, we read in the papers a few weeks ago 
that the shore of one of our Western Islands was covered with seedling 
Apple trees as the result of the wreck of a cargo of Apples, we could 
hardly conclude that the flesh, the core, and the testa of the Apple were- 
adaptations for the dispersal of the pips by the sea. Nevertheless, it is 
worthy of note that the seeds of Asparagus, a fleshy-fruited plant that 
occurs apparently wild at several places along our sea-coast, will withstand; 
