Page:Encyclopædia Britannica, Ninth Edition, v. 24.djvu/259

Rh VINE 237 VINE. Of the grape vines ( Vi tix) V. vinifera is the species best known and longest cultivated ; but out of ten species that grow wild in the United States four (V. rotundifolia, V. Labrusca, V. sestivalis, and V. cordifolia), according to Engelniann, are cultivated and have given origin to numerous derivatives used for wine-making pur poses. Some of the American varieties have been intro duced into France and other countries infested with Phyllo xera, to serve as stocks on which to graft the better kinds of European vines, because their roots, though per haps equally subject to the attacks of the insects, do not suffer so much injury from them as the European species. American vines should not, however, be introduced for grafting or other purposes into a vine-growing country hitherto free from Phylloxera, but only into those in which the insect has already spread. Although the genus Vitis comprises, according to Ben- tham and Hooker, more than two hundred species, mostly natives of tropical or subtropical regions, yet less than half-a-dozen species have any economic value, while the great interest centres in four or five only. Vines have woody climb ing stems, with alternate, palm- ately-lobed, or in some (i.) Vine, (i.) Flower after fall of petals ; magnified, (ii.) Fruit ; reduced, (iii. ) Foliage, tendril, and inflorescence ; reduced. cases (Ampelopsis, Cissus) compound (digitate), leaves, pro vided at the base with small stipules. Opposite some of these leaves springs a tendril, the nature of which is obvi ous from the numerous transitional states it offers between the ordinary form of tendril and the inflorescence. The flowers are small, green, and fragrant, and are arranged in dense clusters. Each has a small calyx in the form of a shallow rim, sometimes four-lobed or five-lobed, or toothed. Within this is an equal number of petals, which in the true vines cohere by their tips and form a cap or hood, which is pushed off when the stamens are ripe. In other species (and as a malformation in the vine itself) the petals are free and spreading. Four or five free stamens, placed opposite the petals, spring from a fleshy ring or disk sur rounding the ovary, each bearing a two-celled anther. The ovary is surmounted by a sessile stigma and is more or less completely two-celled, with two erect ovules in each cell. This ripens into the berry and seed. Planchon, in his monograph of the Ampelidese, (1887), divides the genus Vitis into numerous genera of equal rank. He retains, however, the grape vines under their original name. The cultivated vine has usually hermaphrodite flowers ; but, as it occurs in a wild state, or as an escape from cultivation, the flowers manifest a tendency towards unisexuality : that is, one plant bears flowers with stamens only, or only the rudiments of the pistil, while on another plant the flowers are bisexual. Exclusively female flowers without stamens do not appear to have been observed. Seedling plants from the cultivated vines often produce unisexual flowers, thus reverting to the feral type. Perhaps the ex planation of the fact that some of the cultivated varieties are, as gardeners say, &quot;bad setters,&quot; i.e., do not ripen their fruit owing to imperfect fertilization, is to be sought in this natural tendency to dicecism. The conformation of the vine stem has elicited a vast amount of explanatory comment. The most generally accepted explanation is the &quot; sympodial &quot; one. According to this, the shoot of the vine is a &quot;sympode,&quot; consisting of a number of &quot;podia&quot; placed one over the other in longitudinal series. Each podium consists of a portion of the stem bearing one or more leaves, each with an axil lary bud or buds, and terminating in a tendril or an inflor escence. In V. Labrusca there is a tendril opposite to each leaf, so that the podium bears only a single leaf. In other species there is a definite arrangement of the leaves, some with and others without tendrils opposite to them, the numerical order remaining constant or nearly so. These arrangements have doubtless some reference to climatic phenomena, continuity of growth being arrested by cold and promoted by warmth. In any case it is obvious that these facts might be turned to practical ends in cultiva tion. A vine, for instance, that produces bunches of grapes at each joint is preferable to one in which there are several barren joints, as a larger quantity can be grown within a smaller area. The practice of pruning or &quot;stop ping,&quot; as explained under HORTICULTURE (vol. xii. p. 277), is consciously or unconsciously regulated by the mode of growth. The tendril or inflorescence, according to the views above explained, though in reality terminal, is bent to one side ; hence it appears to be lateral and opposite to the leaf. While the tendril is thus diverted from its orginal direct course, the axillary bud of the leaf opposite the tendril begins a new podium, by lengthening into a shoot which assumes the direction the tendril had prior to its deflexion. This new podium, now in a direct line with its predecessor, produces leaves and ends in its turn in a tendril or inflorescence. A third podium succeeds the second, and so on. Other authorities explain the forma tion of the tendril and its anomalous position opposite to a leaf by supposing that the end of the stem bifurcates during growth, one division forming the shoot, the other the tendril or inflorescence. It is not possible within the limits at our command to specify the facts and arguments by which these theories are respectively supported. Prac tically the tendrils assist the plant in its native state to scramble over rocks or trees. As in the case of similar formations generally, they are endowed with a sensitive ness to touch which enables them to grasp and coil them selves round any suitable object which comes in their way, and thus to support the plant. The tendrils of the Virginian creeper ( Vitis or Ampelopsis hederacea ; the Parti ienocissus quinquefolia of Planchon) are branched, each branch terminating in a little sucker-like expansion by means of which it adheres firmly to walls or rocks. This is especially noticeable in the Japanese species now so commonly grown against walls under the name of Ampelopsis Veitchii (the Parthenocittsun tricuspidata of Planchon). The extremities of these tendrils turn away from the light, and by this means they are enabled to enter crevices, inside which they expand and fix themselves, just as the lewis or key, used by stone-masons, is fixed into blocks of stone. The anomalous position of the stamens in front of the petals is explained by the abortion or non-development of an outer row of stamens, indica tions of which are sometimes seen on the hypogynous disk