four-leaved shamrocks the reader
is referred to Lobel, 'Stirp. Advers.,' Nov., p. 382.
Tabernaemontanus 'Krauterbuch,' S. 222. Schlechtendal, 'Bot.
Zeit.,' ix, p. 583, xiv, p. 71. Maugin, 'Bull. Soc Bot. Fr.,'
1866, t. xiii, p. 279. See also Cramer, 'Bildungsabweich,' p.
92. Walpers, 'Linnaea,' 1840, p. 362 (7-leaved). Schlechtendal,
'Bot. Zeit.,' 1844, p. 457, _Cytisus_. Wigand, 'Flora,' 1856,
p. 706.

Frondiferous leaves have much the appearance of branches provided with
leaves, and they may be compared with those instances in which an
adventitious bud is placed on the surface or edges of the leaves, as in
_Gesnera_, _Cardamine_, &c. In truth, the two conditions merge one into
the other, as in some begonias, where the ramenta often become leaf-like
and bear small bulbils in the axil.

When frondiferous leaves die the appendages die also, but when a true
bud has been formed on a leaf it does not of necessity die with the leaf
that bears it, but separates from it and continues to grow
independently.

=Increased number of stipules, spathes, &c.=--Seringe relates the
occasional presence of two or three additional stipules upon the
leaf-stalks of _Salix fragilis_, and even makes a variety (_Salix
pendula_, var. _multistipulata_).

An increase in the number of the spathes has been often noticed in
Arads[396]. Prof. Alex. Braun has studied this subject in some
detail[397]. In _Calla palustris_ the shoot which continues the growth
of the plant proceeds from the axil of the last leaf but one; the very
last leaf producing no bud, but if accidentally a shoot is developed in
this latter situation it produces flowers at once. No leaves are formed,
but, on the contrary, two or three spathes surround the spadix, so that
the presence of an increased number of spathes in this plant is
associated with the development of a side shoot from the axil of the
last leaf, the situation whence, under natural circumstances, no shoot
at all issues. The supernumerary spathes are not always on the same
level, but may be separated by a considerable interval. They vary very
much in size, and sometimes assume the form and appearance of leaves.
Similar anomalies occur in other Arads as _Arum maculatum_, _Richardia
aethiopica_, and _Anthurium Scherzerianum_, frequently combined with a
leaf-like appearance of the spathes and sometimes with a subdivision of
the spadix into two or three branches.

Engelmann relate