Red or brown-leaved varieties of trees and shrubs also occasionally
produce green-leaved branches, and in this way revert to the type [181]
from which they must evidently have arisen. Instances are on record of
the hazel, _Corylus Avellana_, of the allied _Corylus tubulosa_, of the
red beech, the brown birch and of some other purple varieties. Even the
red bananas, which bear fruits without seeds and therefore have no other
way of being propagated than by buds, have produced a green variety with
yellow fruits. The _Hortensia_ of our gardens is another instance of a
sterile form which has been observed to throw out a branch with cymes
bearing in their center the usual small staminate and pistillate flowers
instead of the large radiate and neutral corollas of the variety,
thereby returning to the original wild type. Crisped weeping-willows,
crisped parsley and others have reverted in a similar manner.
All such cases are badly in need of a closer investigation. And as they
occur only occasionally, or as it is commonly stated, by accident, the
student of nature should be prepared to examine carefully any case which
might present itself to him. Many phases of this difficult problem could
no doubt be solved in this way. First of all the question arises as to
whether the case is one of real atavism, or is only seemingly so, being
due to hybrid or otherwise impure descent of the varying individual, and
secondly whether it may be only an instance of the regularly [182]
occurring so-called atavism of the sporting varieties with which we
shall deal in a later lecture.
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