28 TRANSACTIONS OF THE CANADIAN INSTITUTE. (VoL. VIII 
of them circumstances in progress for long centuries past, the one fitting 
into the other, which have been instrumental in the gradual and wide 
dispersion of many plants. The popular view of the economic purposes 
of fruits is that they are provided by nature as food for man and the 
lower animals. Perhaps an even more immediate purpose in their colour 
and flavour, is that they may attract birds and quadrupeds—as the 
colours of flowers do insects—and that the seeds, by being carried great 
distances in the crops and stomachs of these creatures, should thus have 
an important means of diffusion. 
Wind is, however, the most important factor in distribution. Many 
plants have their seeds furnished with appendages to be utilized in con- 
nection with the wind, and such plants have a generally wider distribu- 
tion than those not so furnished. The different species of maple, ash 
and pine, have what might be termed wings attached to their seeds, 
and these are undoubtedly thus provided that, in falling at maturity, 
the seeds may be carried by the wind beyond the parent tree. The seeds 
of most of the Composite are supplied with plumes or awns which form 
an important means by which they are distributed, and thus this, in 
America, most extensive of the phenogamous orders is, though geologi- 
cally recent, of wide diffusion. Whilst, however, the ordinary winds have 
their local effects in scattering seeds, it is to hurricanes and tornadoés, 
and even ordinary high winds that we must look for the carrying of them 
to great distances. It is not difficult to suppose that most seeds can be 
so carried. Where the fruit is heavy, as in the case of oaks, hickories, 
walnut, butternut, chestnut, plum and cherries, the range of the species 
is relatively circumscribed. The seeds of herbaceous plants are, however, 
as a rule light, almost feathery, in weight—a circumstance which, like 
the awns and wings provided as appendages to many of them, has been, 
without doubt, so arranged by nature that they may be readily distri- 
buted at maturity by the wind. The power of the wind as a distributor 
of the lighter class of seeds has been underestimated. The rapidity 
with which new railroad tracks, extending into newly settled as well 
as old settled country, have become tenanted, not by plants from the 
neighbourhood, but by roving introduced plants, is a striking evidence 
of the action of winds. Most of these introduced plants, so common 
in cultivated fields, on roadsides and on compost heaps, as well as on 
railroad tracks, have seeds relatively light in weight, and provided in 
many instances with appendages to facilitate their dissemination. In 
distr'cts where the forests have been burned over, the native plants 
with which the burned area is soon peopled, are generally of two classes 
—berry-bearing shrubs, the seeds of which have been deposited by pas- 
sing birds, and plants like the fire weed (Epilobium), birch trees and 
willows, whose seeds have wings or awn attachments, which not only 
