is
stage of growth, they would not become irregular. If, moreover, the
arrest were to take place at a still earlier period of development, the
result would be a simple tuft of green leaves; and no one probably
would call this a case of reversion. Dr. Masters designates the cases
first alluded to as regular peloria; and others, in which all the
corresponding parts assume a similar form of irregularity, as when all
the petals in a Linaria become spurred, as irregular peloria. We have
no right to attribute these latter cases to reversion, until it can be
shown to be probable that the parent-form, for instance, of the genus
Linaria had had all its petals spurred; for a change of this nature
might result from the spreading of an anomalous structure, in
accordance with the law, to be discussed in a future chapter, of
homologous parts tending to vary in the same manner. But as both forms
of peloria frequently occur on the same individual plant of the
Linaria,[132] they probably stand in some close relation to each other.
On the doctrine that peloria is simply the result of an arrest of
development, it is difficult to understand how an organ arrested at a
very early period of growth should acquire its full functional
perfection;--how a petal, supposed to be thus arrested, should acquire
its brilliant colours, and serve as an envelope to the flower, or a
stamen produce efficient pollen; yet this occurs with many peloric
flowers. That pelorism is not due to mere chance variability, but
either to an arrest of development or to reversion, we may infer from
an observation made by Ch. Morren,[133] namely, that families which
have irregular flowers often "return by these monstrous growths to
their regular form; whilst we never see a regular flower realise the
structure of an irregular one."

Some flowers have almost certainly become more or less completely
peloric through reversion. _Corydalis tuberosa_ properly has one of its
two nectaries colourless, destitute of nectar, only half the size of
the other, and {59} therefore, to a certain extent, in a rudimentary
state; the pistil is curved towards the perfect nectary, and the hood,
formed of the inner petals, slips off the pistil and stamens in one
direction alone, so that, when a bee sucks the perfect nectary, the
stigma and stamens are exposed an