leaf-bud in the axil of any of the parts of the flower is
not of such common occurrence as the development of a flower-bud in
similar situations, nor is it so frequent as median foliar
prolification. I have seen leafy shoots proceeding from the axils of the
sepals in the flowers of _Brassica_, and a similar occurrence has been
noticed in _Caltha palustris_, _Herreria parviflora_, and other plants.
Dr. Marchand's flowers of _Anagallis_, previously referred to at p. 117,
showed good illustrations of this occurrence, as also some specimens
described by Kirschleger in _A. phoenicea_.[134] Steinheil has figured
and described[135] a flower of _Scabiosa_ in which there was an
adventitious formation of leafy shoots in the axil of the outer calyx.
In some flowers, such as _Convolvulus_, _Anemone_, &c., the exact nature
of the sub-floral leaves is uncertain, _i.e._ it is open to doubt
whether the organs in question are bracts or leaves pertaining to the
inflorescence, or whether they are really parts of the flower. When
leafy shoots are formed in the axils of such organs, the adventitious
growth may be referred to extra-floral prolification, prolification of
the inflorescence that is, or to axillary prolification, according to
the view taken of the real nature of the sub-floral leaves. So far as
the mere occurrence of prolification is concerned, it is not very
material which view be adopted. The same remark applies to cases where
leaf-buds occur on the outer surface of inferior ovaries, as in
_Rosaceae_, _Pomaceae_, _Philadelphus_, or _Tetragonia expansa_, as
elsewhere mentioned.

It would seem more consistent with the general arrangements of parts,
that the adventitious buds should be formed more frequently outside than
within the flower proper.

Knight[136] figures and describes the occurrence of small tubers or
fleshy leaf-buds in the axils of the sepals of a potato, a curious
illustration of the real morphological nature of the tuber.

=Axillary floral prolification of the flower.=--As already stated, this
is of more common occurrence than the formation of a leaf-bud in a
similar situation. Any of the parts of the flower may thus subtend a
flower-bud, though probably the new buds more frequently originate in
the axils of the sepals than in the other whorls. In _Cruciferae_ the
change in question is, relatively speaking, very common. In cauliflowers
and broccoli I have frequently met with stalked flowers proceeding from
the