int of junction between the two old kinds.

To sum up the foregoing facts: the statement that _Cytisus adami_
originated as a graft-hybrid is so precise that it can hardly be rejected,
and, as we have just seen, some analogous facts render the statement to a
certain extent probable. The peculiar, monstrous condition of the ovules,
and the apparently sound condition of the pollen, favour the belief that it
is not an ordinary or seminal hybrid. On the other hand, the fact that the
same two species, viz. _C. laburnum_ and _purpureus_, have spontaneously
produced hybrids by seed, is a strong argument in support of the belief
that C. _adami_ originated in a similar manner. With respect to the
extraordinary tendency which this tree exhibits to complete or partial
reversion, we have seen that undoubted seminal hybrids and mongrels are
similarly liable. On the whole, I am inclined to put trust in M. Adam's
statement; and if it should ever be proved true, the same view would
probably have {397} to be extended to the Bizzarria and Trifacial oranges
and to the apples above described; but more evidence is requisite before
the possibility of the production of graft-hybrids can be fully admitted.
Although it is at present impossible to arrive at any certain conclusion
with respect to the origin of these remarkable trees, the various facts
above given appear to me to deserve attention under several points of view,
more especially as showing that the power of reversion is inherent in Buds.

* * * * *

_On the direct or immediate action of the Male Element on the Mother
Form._--Another remarkable class of facts must be here considered, because
they have been supposed to account for some cases of bud-variation: I refer
to the direct action of the male element, not in the ordinary way on the
ovules, but on certain parts of the female plant, or in the case of animals
on the subsequent progeny of the female by a second male. I may premise
that with plants the ovarium and the coats of the ovules are obviously
parts of the female, and it could not have been anticipated that they would
be affected by the pollen of a foreign variety or species, although the
development of the embryo, within the embryonic sack, within the ovule,
within the ovarium, of course depends on the male element.

Even as long ago as 1729 it was observed[928] that white and blue
varieties of the Pea, when planted near each other, mu