t leaves and manner of growth, is a
surprising sight. The same raceme sometimes bears two kinds of flowers;
and I have seen a single flower exactly divided into halves, one side
being bright yellow and the other purple; so that one half of the
standard-petal was yellow and of larger size, and the other half purple
and smaller. In another flower the whole corolla was bright yellow, but
exactly half the calyx was purple. In another, one of the dingy-red
wing-petals had a bright yellow narrow stripe on it; and lastly, in
another flower, one of the stamens, which had become slightly
foliaceous, was half yellow and half purple; so that the tendency to
segregation of character or reversion affects even single parts {388}
and organs.[899] The most remarkable fact about this tree is that in
its intermediate state, even when growing near both parent-species, it
is quite sterile; but when the flowers become pure yellow or pure
purple they yield seed. I believe that the pods from the yellow flowers
yield a full complement of seed; they certainly yield a large number.
Two seedlings raised by Mr. Herbert from such seed[900] exhibited a
purple tinge on the stalks of their flowers; but several seedlings
raised by myself resembled in every character the common laburnum, with
the exception that some of them had remarkably long racemes: these
seedlings were perfectly fertile. That such purity of character and
fertility should be suddenly reacquired from so hybridized and sterile
a form is an astonishing phenomenon. The branches with purple flowers
appear at first sight exactly to resemble those of _C. purpureus_; but
on careful comparison I found that they differed from the pure species
in the shoots being thicker, the leaves a little broader, and the
flowers slightly shorter, with the corolla and calyx less brightly
purple: the basal part of the standard-petal also plainly showed a
trace of the yellow stain. So that the flowers, at least in this
instance, had not perfectly recovered their true character; and in
accordance with this, they were not perfectly fertile, for many of the
pods contained no seed, some produced one, and very few contained as
many as two seeds; whilst numerous pods on a tree of the pure _C.
purpureus_ in my garden contained three, four, and five fine seeds. The
pollen, moreover, was