Fig. 478.—Branch with bunch of grapes.
Fig. 479.—Diagram of the position of leaf and tendrils. The branch is divided into sections on the sympodial theory (the successive generations, I, II, III, IV, are alternately white and shaded); k buds.
Fig. 480.—A Flower throwing off the corolla; B flower after the removal of the corolla; C, D longitudinal and transverse section of seed; E longitudinal section of gynœceum; s calyx.
Fig. 481.—Diagram of branch and position of leaves; sl tendril; lt the main axis; ax stipules of the foliage-leaf shown below; g axillary-bud (the dwarf-branch); v its fore-leaf; l1 l2 its first two foliage-leaves with their stipules; lt1 long-branch in the axil of v (everything appertaining to this branch is entirely black); v1 the first leaf of this branch.
Vitis and Ampelopsis (5-merous flowers); Cissus (4-merous flower); Leea (without stipules, corolla gamopetalous). The inflorescence in Pterisanthes (E. Ind.) has a peculiar, flat, leaf-like axis, on the edges of which ♂-flowers are borne, and on the surface ♀-flowers.
The TENDRILS in Ampelidaceæ are modified branches, since they bear leaves and may be abnormally developed as branches with foliage-leaves, and finally the inflorescences are borne in the position of the tendrils, and tendrils are met with which are partly inflorescences. The explanation of the position of the tendril, namely, right opposite the foliage-leaf but without a subtending-leaf, has been much disputed. The relative positions are as follows: in Vitis vinifera the following two kinds of shoots and relative positions are found (the other species deviate in one or other particular), (a) Long-branches, which have 2 scale-leaves and a large number of foliage-leaves with a divergence of 1/2; opposite the lowest 3–5 foliage-leaves no tendrils are found, then follow: 2 foliage-leaves with tendrils, 1 without a tendril, 2 with and 1 without, etc., with great regularity. Buds are developed in the axils of the foliage-leaves (Fig. [479]): these develop into (b) DWARF-BRANCHES, which commence with 1 laterally-placed scale-leaf (fore-leaf; Fig. [481] v) succeeded by several foliage-leaves with a divergence of 1/2 (in a plane at right angles to that of the mother-shoot), but the whole shoot is extremely small, and often dries up and drops off in the autumn, so that only the scale-leaf, v, with the bud (Fig. [481] lt1) in its axil remains. This bud in the following year developes into a new long-branch, and since its leaves lie in a plane at right angles to that of the dwarf-branch, their plane coincides with that of the long-branch from which it is developed (the grandmother axis).—The tendrils no doubt may most correctly be regarded as the modified main axis which has been pushed aside by a lateral branch. The branches are then sympodia, whose successive shoots bear alternately 1 and 2 foliage-leaves: thus, on the figure there are portions altogether of 5 shoots (I.-V.), the 1-leaved ones are shaded, the 2-leaved ones are white. The following facts however are adverse to this theory: (1) the first leaf on an axillary bud is then situated 180° from the subtending leaf (e.g. the lowermost shaded leaf, Fig. [479], 180° from the lowermost white leaf), whilst the rule in the Dicotyledons is that it is placed only about 90° to one side. (2) The buds (Fig. [479] K) from which the dwarf-branches develop, must then be accessory and sister-buds to the sympodial shoots, but their first leaves have a different relative position to this, which is very peculiar, and a still more remarkable fact is that the buds, K, etc. are similar in structure and present in all the axils; thus we only find accessory buds in the cases where no tendrils are opposite to the leaves, and the main bud must then be considered to be suppressed. (3) The development proves that the tendrils arise on the side of a vigorous growing-point of the stem or by its division, and do not develop, as might be expected, from the apex of the shoot. But these relations however, find their analogues and are all capable of explanation, whereas other less natural modes of explanation are opposed to them.
435 species; especially in the Tropics; they are rarer in America. In N. Am. some Vitis-species and Ampelopsis quinquefolia are found. Vitis vinifera is supposed to have originated in the districts East and South of the Caspian Sea. Wine is obtained from Vitis-species, especially V. vinifera, and “raisins,”—(the name “currants,” given to a special variety with small, seedless fruits, is derived from Corinth).—The species of Ampelopsis (Virginian Creeper) are cultivated as ornamental plants.