Page:The New International Encyclopædia 1st ed. v. 12.djvu/831

MALFOBMATION. 739 MAI-FOEMATION. of a ring of tissue uuderueatli the developing separate rudiments, carrying these upward on the edge of a growing cup or C3'linder. (See Flower.) Actual union is due to the adhesion of young surface cells of organs which are closely crowded as they are forming. The union is seldom firm, and slight pressure suf- fices to separate the adherent parts with- out real tearing. (4) Fcisciafion. — Stems, normally cylindrical, sometimes develop in a flattened form, sev- eral to many times the ordinary diam- FiG. 2. SOLUTION OF THE FLOWER ctcr in oue direction pAETs. and not unusually Longitudinal section of apple thickened in the blcssom. Tlie calyx, petals, and Qt^er (Fi" 1 ) Xot stamens are normally closely . , * ^i^' i united into a mass about the infrequently one edge pistils. Here each set is dis- of this broad stem ™*- grows more rapidly than the other, when it becomes curved edgewise, riosier-like. The ridges and grooves on the surface >>iggest the union of several normal stems. Con- trary to appearance, however, such stems are not ordinarily due to congenital union of independent .-.tems. each from a single Inid. but are produced by the simultaneous development of several buds in line. Fasciation is very common in rapidly growing stems, which are abundantly supplied with food and water. The young shoots of asparagus, the flower stalks (scapes) of the dandelion, and young shoots from severely pruned trees frequently furnish fine examples. (5) Solution. — In most seed plants some of the foliar or floral structures are ordinarily develoiied in circles or whorls or in a crowded spiral. If nowhere else, this is certain to occur in the flow- ers. (Fig. 2.) Sometimes the stem develops between the points of attachment of these nor- mally crowded leaves, separating them unusually. Thus it comes that flower leaves are sometimes separated by consider- able lengths of stem and the flower loses its' char- acteristic form. Xot in- frequently at the same time the petals lose their brighter hues and become greenish. (6) Proliferation is a con- tinued growth of an axis whose growth is normally finished, or the development of a branch from growing points which ordinarily either are not formed at all or remain dormant. Thus the formation of a flower usually checks the terminal growth of the axis on which it oc- curs, but in the pear and apple it not infre- quently resumes its growth after the fruit has begun to form and develops a leafy twig be- yond it. (Fig. 3.) In a similar way, a flower cluster, such as the head in asters and sun- flowers, ordinarily checks the growth of the axis, but occasionally it is prolonged through Fig. 3. PROLIFERATION. Strawberry with axis nor- niall.v sttipped b.v flower prolonged into a leafy shoot after fruiting. the cluster, leaving it surrounding the stem. While branches ordinarily occur in the axils of foliage leaves, they do not usually develop in the axils of floral leaves. This may occur, however, and a short branch bearing a complete flower may arise in the axil of each petal or .sepal. (Fig. 4.) Some double flowers are made extra-double by this sort of proliferation. A form of prolifera- tion in the flower, when the branches show a tendency to separate readily from the parent, to 2. Longitudinal section. 1. External view. Fig. 4. PROLIPEROC9 ROSE. The ' hip ' is absent : sepals, s, leaf-like; petals, p, unaffect- ed ; above them a circle, st, of miniature roses with numer- ous petals, stamens, etc.; c, scales in many rows ; above these a whorl of five foliage leaves. The axis is pro- longed above the cal.vx and beyond the scales, carrying foliage leaves and a flower bud. develop roots, or to become bulb-like and repro- duce the plant readily, is called vivipary (q.v. ). (7) Torsion. — Stems normally straight, or leaves normally flat, may through more extensive growth of one part or another be twisted or crinkled. Lettuce leaves show a crispate form on a large scale (Fig. 6) and twisted stems are extreme- ly common. (S) Abnormal branching of leaves is not infrequent. Clover leaves, normally with three leaf- lets (branches), are often found with four or five, or even as many as seven. The leaves of the dahlia, hickory (Fig. 7), and many other plants show similar deviations from the let. flve-spurred sepals normal. Abnonnally re- ^i^^^^" normally peated branching in flower clusters is also common (Fig. 8). (9) Peloria. — Irregular flowers, that is, those in which some Fio. 5. Regular peloria of vio-