aid that they are subject to quite
uniform conditions, and they are liable to a certain amount of variation.
The circumstances under which our domestic productions are reared are
widely different: they are protected from competition; they have not only
been removed from their natural conditions and often from their native
land, but they are frequently carried from district to district, where they
are treated differently, so that they never remain during a considerable
length of time exposed to closely similar conditions. In conformity with
this, all our domesticated productions, with the rarest exceptions, vary
far more than natural species. The hive-bee, which feeds itself and follows
in most respects its natural habits of life, is the least variable of all
domesticated animals, and probably the goose is the next least variable;
but even the goose varies more than almost any wild bird, so that it cannot
be affiliated with perfect certainty to any natural species. Hardly a
single plant can be named, which has long been cultivated and propagated by
seed, that is not highly variable; common rye (_Secale cereale_) has
afforded fewer and less marked varieties than almost any other cultivated
plant;[606] but it may be doubted whether the variations of this, the least
valuable of all our cereals, have been closely observed.

Bud-variation, which was fully discussed in a former chapter, shows us that
variability may be quite independent of seminal reproduction, and likewise
of reversion to long-lost ancestral characters. No one will maintain that
the sudden appearance {255} of a moss-rose on a Provence-rose is a return
to a former state, for mossiness of the calyx has been observed in no
natural species; the same argument is applicable to variegated and
laciniated leaves; nor can the appearance of nectarines on peach-trees be
accounted for with any probability on the principle of reversion. But
bud-variations more immediately concern us, as they occur far more
frequently on plants which have been highly cultivated during a length of
time, than on other and less highly cultivated plants; and very few
well-marked instances have been observed with plants growing under strictly
natural conditions. I have given one instance of an ash-tree growing in a
gentleman's pleasure-grounds; and occasionally there may be seen, on beech
and other trees, twigs leafing at a different period from the other
branches. But our forest trees in England