the front of the adventitious lobe is
directed towards the corresponding surface of the original petal, thus
[Symbol: () turned 90 degrees]. Whether these supernumerary petals are
formed by chorisis or by enation cannot, with certainty, be determined
without examining the early stages of development.

[Illustration: FIG. 212.--_Datura fastuosa._ True corolla turned back to
show the supernumerary corolla with the petal-like segments attached to
its outer surface (reduced).]

Of more interest are those instances where the adventitious growth is on
the outside of the corolla; thus in a garden azalea there was
intermediate between the calyx and the corolla, both of which were
normal, a series of five petalodes, alternating with the sepals, and,
therefore, opposite to the lobes of the corolla, and adherent with them
at the very base, though elsewhere detached. These petalodes were
concave on the surface looking towards the calyx, and were there
brightly coloured, while the tint of the opposite surface looking
towards the corolla was of a duller hue, corresponding with that of the
outside of the corolla-tube. This arrangement of the colour was thus
precisely similar to that which occurred in the four-winged leaves
already referred to at p. 446. In some flowers of _Datura fastuosa_ a
similar series of excrescences was observed; the calyx and the corolla
were normal within the latter, intervening between it and the stamens
was a second corolla produced by duplication, and adherent to the inner
surface of this latter were five stamens. So far there was nothing very
peculiar; it remains to say, however, that on the outer surface of the
second corolla were five petal-like lobes closely adherent to it below,
but partially detached above. The colour of the adventitious segments
was paler on the outside than on the inner surface, as in the corolla
itself. The position of the several parts was such that they were
opposite one to the other; hence, while the lobes of the inner corolla
were opposite to those of the outer one, the intermediate petalodes were
opposite to both; thus:

S S S S S
--------------------------
P P P P P
X X X X X
--------------------------
P P P P P
st st st st st

The X indicating the position of the petalodes.

[Illustration: FIG. 213.--Gloxinia, with supernumerary segments on the
outside of the t