orm of
the seeds, in the colour of the anthers, in the cotyledons being of
immense size, in new and highly peculiar odours, in the flowers
expanding early in the season, and in their closing at night. With
respect to one lot of these hybrids, he remarks that they presented
characters exactly the reverse of what might have been expected from
their parentage.[637]

Prof. Lecoq[638] speaks strongly to the same effect in regard to this
same genus, and asserts that many of the hybrids from _Mirabilis
jalapa_ and _multiflora_ might easily be mistaken for distinct species,
and adds that they differed in a greater degree, than the other species
of the genus, from _M. jalapa_. Herbert, also, has described[639] the
offspring from a hybrid Rhododendron as being "as _unlike all others_
in foliage, as if they had been a separate species." The common
experience of floriculturists proves that the crossing and recrossing
of distinct but allied plants, such as the species of Petunia,
Calceolaria, Fuchsia, Verbena, &c., induces excessive variability;
hence the appearance of quite new characters is probable. M.
Carriere[640] has lately discussed this subject: he states that
_Erythrina cristagalli_ had been multiplied by seed for many years, but
had not yielded any varieties: it was then crossed with the allied _E.
herbacea_, and "the resistance was now overcome, and varieties were
produced with flowers of extremely different size, form, and colour."

From the general and apparently well-founded belief that the crossing
{266} of distinct species, besides commingling their characters, adds
greatly to their variability, it has probably arisen that some
botanists have gone so far as to maintain[641] that, when a genus
includes only a single species, this when cultivated never varies. The
proposition made so broadly cannot be admitted; but it is probably true
that the variability of cultivated monotypic genera is much less than
that of genera including numerous species, and this quite independently
of the effects of crossing. I have stated in my 'Origin of Species,'
and in a future work shall more fully show, that the species belonging
to small genera generally yield a less number of varieties in a state
of nature than those belonging to large genera. Hence the species of
small genera would, it is probable