Fig. 176.—Interrupted growth in Apple.
Fig. 175 shows an instance of the kind in a radish, and fig. 176 a similar deformity in the case of an apple, the dilatation of the flower-stalk below the ordinary fruit producing an appearance as if there were two fruits one above another.
In leaves this peculiar irregularity of development is more common.
In some varieties of Codiæum variegatum the leaves resemble those of Nepenthes, as the basal portion is broad, and terminates in a projecting midrib destitute of cellular covering, and this again terminates in a small pouch or pitcher. Somewhat similar variations may be found in ferns, especially Scolopendrium vulgare.
Instead of the pouch there is formed sometimes in the plant last mentioned a supplementary four-lobed lamina, the four lobes being in two different planes, and diverging from the midrib, so that the section would resemble [symbol: Sideways X], the point of intersection of the x representing the position of the midrib. This four-winged lamina is thus very similar to the four-winged filaments described and figured at p. 289, and to the leaf-like anther of Jatropha described by M. Müller, p. 255.
Cornute leaves (Folia cornuta).—The condition to which this term applies is that in which the midrib, after running for a certain distance, generally nearly to the point of the leaf, suddenly projects, often in a plane different from that of the leaf, and thus forms a small spine-like out-growth. Should this happen to be terminated by a second laminar portion, an interrupted leaf would be formed. In Scolopendrium vulgare and other ferns this condition has been noticed, as also in some of the varieties of Codiæum variegatum already referred to.
Flattening.—There are some plants whose stem or branches, instead of assuming the ordinary cylindrical form, are compressed or flattened; such are some species of Epiphyllum, Coccoloba, Bauhinia, &c. The same thing occurs in the leaf-like branches of Ruscus, the flower-stalks of Xylophylla, Phyllanthus, Pterisanthes. Martins proposes to apply the word 'cladodium' to such expansions, just as the term phyllodium is applied to the similar dilatation of the leaf-stalks. If we exclude instances of fasciation, i.e. where several branches are fused together and flattened, we must admit that this flattening does not occur very often as a teratological appearance.
Mr. Rennie figures and describes a root of a tree which had become greatly flattened in its passage between the stones at the bottom of a stream, and had become, as it were, moulded to the stones with which it came into contact.[364]