But if the tree annually produced 50,000 flowers,
of which the self-fertilised dropped off without yielding seeds, then
the cross-fertilised flowers might yield seeds in sufficient number to
keep up the stock, and most of the seedlings would be vigorous from
being the product of a cross between distinct individuals. In this
manner the production of a vast number of flowers, besides serving to
entice numerous insects and to compensate for the accidental destruction
of many flowers by spring-frosts or otherwise, would be a very great
advantage to the species; and when we behold our orchard-trees covered
with a white sheet of bloom in the spring, we should not falsely accuse
nature of wasteful expenditure, though comparatively little fruit is
produced in the autumn.
ANEMOPHILOUS PLANTS.
The nature and relations of plants which are fertilised by the wind have
been admirably discussed by Delpino and Hermann Muller; and I have
already made some remarks on the structure of their flowers in contrast
with those of entomophilous species. (10/42. Delpino 'Ult. Osservazioni
sulla Dicogamia' part 2 fasc. 1 1870 and 'Studi sopra un Lignaggio
anemofilo' etc. 1871. Hermann Muller 'Die Befruchtung' etc. pages 412,
442. Both these authors remark that plants must have been anemophilous
before they were entomophilous. Hermann Muller further discusses in a
very interesting manner the steps by which entomophilous flowers became
nectariferous and gradually acquired their present structure through
successive beneficial changes.
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