very imperfect, a multitude of grains being small
and shrivelled; and this is a singular fact; for, as we shall
immediately see, the pollen-grains in the dingy-red and sterile flowers
on the parent-tree, were, in external appearance, in a much better
state, and included very few shrivelled grain. Although the pollen of
the reverted purple flowers was in so poor a condition, the ovules were
well-formed, and, when mature, germinated freely with me. Mr. Herbert
also raised plants from seeds of the reverted purple flowers, and they
differed _very little_ from the usual state of _C. purpureus_; but this
expression shows that they had not perfectly recovered their proper
character.

Prof. Caspary has examined the ovules of the dingy-red and sterile
flowers in several plants of _C. adami_ on the Continent,[901] and
finds them generally monstrous. In three plants examined by me in
England, the ovules were likewise monstrous, the nucleus varying much
in shape, and projecting irregularly beyond the proper coats. The
pollen-grains, on the other hand, judging from their external
appearance, were remarkably good, and readily protruded their tubes. By
repeatedly counting, under the microscope, the proportional number of
bad grains, Prof. Caspary ascertained that only 2.5 per cent. were bad,
which is a less proportion than in the pollen of three pure species of
Cytisus in their cultivated state, viz. _C. purpureus_, _laburnum_, and
_alpinus_. Although the pollen of _C. adami_ is thus in appearance
good, it does not follow, according {389} to M. Naudin's
observations[902] on Mirabilis, that it would be functionally
effective. The fact of the ovules of _C. adami_ being monstrous, and
the pollen apparently sound, is all the more remarkable, because it is
opposed to what usually occurs not only with most hybrids,[903] but
with two hybrids in the same genus, namely in _C. purpureo-elongatus_,
and _C. alpino-laburnum_. In both these hybrids, the ovules, as
observed by Prof. Caspary and myself, were well-formed, whilst many of
the pollen-grains were ill-formed; in the latter hybrid 20.3 per cent.,
and in the former no less than 84.8 per cent. of the grains were
ascertained by Prof. Caspary to be bad. This unusual condition of the
male and female reproductive elements in _C. adami_ has been used by
Prof. C