roduced by another variety or species, is a
subject which I shall fully discuss in the following chapter.

The second remarkable fact is that two supposed hybrids[633] (for their
hybrid nature was not ascertained) between an orange and either a lemon
or citron produced, on the same tree, leaves, flowers, and fruit of
both pure parent-forms, as well as of a mixed or crossed nature. A bud
taken from any one of the branches and grafted on another tree produces
either one of the pure kinds or a capricious tree reproducing the three
kinds. Whether the sweet lemon, which includes within the same fruit
segments of differently flavoured pulp,[634] is an analogous case, I
know not. But to this subject I shall have to recur.

I will conclude by giving from A. Risso[635] a short account of a very
singular variety of the common orange. It is the "_citrus aurantium
fructu variabili_," which on the young shoots produces rounded-oval
leaves spotted with yellow, borne on petioles with heart-shaped wings;
when these leaves fall off, they are succeeded by longer and narrower
leaves, with undulated margins, of a pale-green colour embroidered with
yellow, borne on foot-stalks without wings. The fruit whilst young is
pear-shaped, yellow, longitudinally striated, and sweet; but as it
ripens, it becomes spherical, of a reddish-yellow, and bitter.

_Peach and Nectarine (Amygdalus Persica)._ The best authorities are
{337} nearly unanimous that the peach has never been found wild. It was
introduced from Persia into Europe a little before the Christian era,
and at this period few varieties existed. Alph. De Candolle,[636] from
the fact of the peach not having spread from Persia at an earlier
period, and from its not having pure Sanscrit or Hebrew names, believes
that it is not an aboriginal of Western Asia, but came from the _terra
incognita_ of China. The supposition, however, that the peach is a
modified almond which acquired its present character at a comparatively
late period, would, I presume, account for these facts; on the same
principle that the nectarine, the offspring of the peach, has few
native names, and became known in Europe at a still later period.

[Illustration: Fig. 42.--Peach and Almond Stones, of natural size,
viewed edgeways. 1. Common English Peach. 2. Double, crimson-flowered,
Chinese Pea