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Variation of Animals and Plants under Domestication, the — Volume 2 by Charles Darwin
page 21 of 776 (02%)
their appearance; and these can afterwards by care be multiplied by seed.

The stripes and segments just referred to are not due, as far as is known, to
reversion to characters derived from a cross, but to characters lost by
variation. These cases, however, as Naudin (13/22. 'Nouvelles Archives du
Museum' tome 1 page 25. Alex. Braun (in his 'Rejuvenescence' Ray Soc. 1853
page 315) apparently holds a similar opinion.) insists in his discussion on
disjunction of character, are closely analogous with those given in the
eleventh chapter, in which crossed plants have been known to produce half-and-
half or striped flowers and fruit, or distinct kinds of flowers on the same
root resembling the two parent-forms. Many piebald animals probably come under
this same head. Such cases, as we shall see in the chapter on Crossing,
apparently result from certain characters not readily blending together, and,
as a consequence of this incapacity for fusion, the offspring either perfectly
resemble one of their two parents, or resemble one parent in one part, and the
other parent in another part; or whilst young are intermediate in character,
but with advancing age revert wholly or by segments to either parent-form, or
to both. Thus, young trees of the Cytisus adami are intermediate in foliage
and flowers between the two parent-forms; but when older the buds continually
revert either partially or wholly to both forms. The cases given in the
eleventh chapter on the changes which occurred during growth in crossed plants
of Tropaeolum, Cereus, Datura, and Lathyrus are all analogous. As, however,
these plants are hybrids of the first generation, and as their buds after a
time come to resemble their parents and not their grandparents, these cases do
not at first appear to come under the law of reversion in the ordinary sense
of the word; nevertheless, as the change is effected through a succession of
bud-generations on the same plant, they may be thus included.

Analogous facts have been observed in the animal kingdom, and are more
remarkable, as they occur in the same individual in the strictest sense, and
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