This subdivision of axial organs is not unfrequently the result of some injury or mutilation, thus Duval Jouve alludes to the frequency with which branched stems are produced in the various species of _Equisetum_, as a consequence of injuries to the main stem, but this is rather to be considered as a multiplication of parts than as a subdivision of one. [Illustration: FIG. 26.--Bifurcated leaf of _Lamium album_, &c.] =Fission of foliar organs.=--Many leaves exhibit constantly the process of fission, such as the _Salisburia adiantifolia_, and which is due perhaps as much to the absence or relatively small proportion of cellular as compared with vascular tissue, as to absolute fission. In the same way we have laciniated leaves of the Persian lilac, _Syringa persica_, and Moquin mentions instances in a species of _Mercurialis_ in which the leaves were deeply slashed. In _Chenopodium Quinoa_ the leaves were so numerous and the clefts so deep, that the species was hardly recognisable, while on a branch of _Rhus Cotinus_ observed by De Candolle the lobes were so narrow and so fine as to give the plant the aspect of an _Umbellifer_. Wigand ('Flora,' 1856, p. 706) speaks of the leaves of _Dipsacus fullonum_ with bi-partite leaves; Moquin mentions the occurrence of a leaf of an oleander bi-lobed at the summit, so as to give the appearance of a fusion of two leaves. Steinheil has recorded an instance in _Scabiosa atropurpurea_ in which one of the stem leaves presented the following peculiarities. It was simple below, but divided above into two equal lobes, provided each with a median nerve.[71] Steinheil has also recorded a _Cerastium_ in which one of the leaves was provided with two midribs; above this leaf was a group of ternate leaves. I have seen similar instances in the common Elm, _Ulmus campestris_, and also in the common nettle, _Urtica dioica_, the leaves of which latter thus resembled those of _Urtica biloba_, which are habitually bilobed at the summit. M. Clos[72] mentions an instance where the terminal leaf and first bract of _Orchis sambucina_ were divided into two segments. The same author also mentions the leaves of _Anemiopsis californica_, which were divided in their upper halves each into two lobes--also leaves of a lentil springing from a fasciated stem and completely divided into two segments, but with only a single bud in the axil. The axillary branches in like manner showed traces of cleavage. Fig. 26 represents a case of this kind in _Lamium album_, conjoined with suppression of the flowers on one side of the stem. I have also in my herbarium a leaf of _Arum maculatum_, with a stalk single at the base, but dividing into two separate stalks, each bearing a hastate lamina, the form of which is so perfect that were it not from the venation of the sheath it would be considered that there was here a union of two leaves rather than a bifurcation of one. A garden Pelargonium presented the same appearance.