History of Study and Origin

The grapevine species Vitis æstivalis was clearly identified and described by the researcher Michaux, firmly retaining its original botanical name. For a long time, the independent species Vitis lincecumii and Vitis cinerea were mistakenly attributed to this species. The herbarium of the Philadelphia Academy houses a vine specimen collected by Leconte under the name Vitis araneosa, which represents a form of Vitis æstivalis with the abundant rust-felted pubescence characteristic of the Atlantic coast.

The researcher J.-E. Planchon confirmed that Vitis sinuosa, described by Bosc, is pure Vitis æstivalis. Rafinesque's descriptions (in his manual of American vines), cross-referenced with their habitats, also allow his species Vitis bracteata, Vitis multiloba, and Vitis ursina to be classified as weakly differentiated forms of Vitis æstivalis. The scientist Engelmann isolated the "Southern Æstivalis" group within the species, including the cultivated varieties Herbemont, Jaquez, and Rulander, which are characterized by whitish pubescence on the lower veins of less jagged leaves. However, the scientist Millardet proved that most of these vines are hybrids of the species Vitis æstivalis and Vitis cinerea. The viticulturist-researcher T. V. Munson mistakenly classified this southern group as an independent species, Vitis Bourquina (or Bourquiniana).

Geographical Distribution

Vitis æstivalis is the predominant species in the central and central-eastern parts of the United States of America. The highest density of wild populations has been recorded in Pennsylvania, Virginia, Carolina, as well as in the small Atlantic states of Maryland, Delaware, and New Jersey. The natural geographical boundary of the range is delineated by New England, the Great Lakes region, northern Illinois and Iowa, the Indian Territory, and Texas. The vine is found in the eastern Gulf States, including Louisiana and northern Florida (where its hybrid forms predominate). Separate specimens have been recorded in northern Texas, and the Washington herbaria contain specimens collected in northern Mexico. This species is inferior in population density to the species Vitis riparia, Vitis candicans, and Vitis cordifolia, but it is not rare.

Soil and Climatic Conditions of Growth

In the wild, the vine develops under a temperate climate, demonstrating high resistance to severe heat and harsh winter frosts. The plant grows in various conditions—from river floodplains to dry uplands, but completely avoids swampy lowlands and marshes. The trunks reach their greatest development on the fertile alluvial deposits of Maryland and Carolina.

The main part of the natural range of the species is confined to ancient geological formations: granitic, Silurian, Devonian, Cambrian, and Carboniferous (of the Azoic and Paleozoic eras). The soils of these zones are predominantly stony, intensely colored red, and rich in siliceous elements. In Maryland, the vine grows on red sands with a high humus content. As an exception, the species occurs on dry soils composed of grayish compact limestone gravel in southeastern Missouri, as well as on the whitish marls of Tennessee, where the vine retains the green color of its leaves but forms a slender trunk and weak annual growth. On the rich blue marls of Missouri, the species maintains its vegetative vigor without signs of chlorosis. However, on pure chalky soils, the vine possesses extremely low resistance to lime-induced chlorosis, especially when grafted.

Synonyms

  • Vitis æstivalis Michaux
  • Vitis araneosa Leconte
  • Vitis sinuosa Bosc
  • Vitis bracteata Rafinesque
  • Vitis ursina Rafinesque
  • Vitis multiloba Rafinesque
  • Vitis incisifolia Davin
  • Vitis bourquiniana T.-V. Munson
  • Vitis bourquina T.-V. Munson (partim)
  • Vitis sylvestris, Vitis americana, Vitis occidentalis Bert.
  • Vitis nortoni Prince
  • Vitis labrusca var. æstivalis Regel
  • Summer Grape
  • Chicken Grape
  • Pigeon Grape
  • Rusty Grape
  • Little Grape
  • Bunch Grape
  • Southern Æstivalis

Morphological Description of the Vine and Shoots

The plant forms high-vigor climbing vines with a pronounced climbing habit; in the absence of supports, the bushes acquire a semi-erect form. In forest tracts, the vine climbs into the crowns of medium-tall forest trees or completely covers shrubs on dry areas. The trunk is powerful, and in conditions of rich and fresh soils, its circumference reaches 50 centimeters; separate specimens with trunks up to 1 meter 30 centimeters in circumference have been recorded. The wood is hard and fibrous; beneath the tough bark, which exfoliates in irregular strips, the wood layer is grayish-purple.

  • Buds and young leaves: the buds are small, frequently arranged in twos or threes, and colored an intense dark golden-rusty color, later turning into a purple shade; the covering scales are wide and transparent. In the herbaceous state, the young leaves are thick, covered with a continuous, dense layer of cobwebby down on both sides, and colored a pinkish-carmine, which as the leaf develops is retained exclusively along its margin.
  • Inflorescences: small, colored a dark brownish-red. At the beginning of the growing season, they are completely enclosed in long bracts, which gives the inflorescences a specific appearance reminiscent of a pine cone. The calyx is rudimentary; the filaments are long and slender; the ovary is short, swollen, provided with a short style and a bifid stigma.
  • One-year-old shoots: long, of medium thickness, in some forms relatively slender, and slightly wavy. The surface of the shoot is covered with numerous regular, fine, clearly defined longitudinal grooves. At the level of the nodes, which are weakly pronounced and have slight thickening, the shoots expand noticeably. Upon maturation, the shoot acquires a matte, dark wine coloration; its surface becomes slightly rough due to the presence of short stiff hairs on the nodes and at the base, and in individual forms, the pubescence is arranged in the form of rusty-colored flakes. In the herbaceous state, the shoots have a purple coloration of varying intensity and bear dense rusty down at their apices.
  • Internal structure of the shoot: the wood has a greenish tint on the fracture. The dense, homogeneous pith occupies no more than a third of the total diameter of the shoot and is colored a pinkish-white. The diaphragms are thick (up to 3 millimeters), concave, with a clearly outlined boundary from the side of the shoot apex and a diffuse transition at its base.
  • Tendrils: the arrangement is discontinuous. The tendrils are powerful, noticeably widened at the point of attachment, and divided into two or three branches. In the herbaceous state, they are colored purple and covered with flocculent down of a white or rusty shade.

Characteristics of Leaves

The leaves are medium or almost large, with dimensions averaging 17 centimeters in length and 15 centimeters in width (the length exceeds the width). The shape of the leaf blade is elongated-round, widened at the base, sometimes acquiring pentagonal contours, with weak asymmetry. Depending on geographical conditions, the dissection of the blade varies greatly: in northern states, deeply dissected three- or five-lobed leaves with rhomboidal sinuses forming lyre-shaped lobes predominate (the terminal lobe is especially clearly defined); in southern regions, almost entire leaves are more common, in which the lobes are marked only as small sinuses. Each of the lobes necessarily terminates in a longer and sharper tooth.

  • Texture and blade: flat, finely reticulate (wrinkled) between the veins, which are distinctly depressed on the upper side of the blade. In forms from southern dry soils, the blade is very thick, dense, and leathery (parchment type); in northern types, it is thinner. Bullated surfaces occur very rarely.
  • Sinuses and teeth: the petiolar sinus is deep, having the shape of a relatively open letter V on entire leaves, and on deeply dissected leaves, it becomes rhomboidal and widens noticeably at its base. The teeth are of two types: either very wide, flat, smoothed, and barely noticeable, or regular, moderately sharp, triangular in shape, directed toward the apex of the leaf and terminating in a distinct stiff point.
  • Pubescence and color: the upper side of the leaf is colored a matte dark green; it is hairless or retains sparse flakes of cobwebby hairs along the main veins. The lower surface has a paler coloration, sometimes with a characteristic brick or watery-green tint of the tissue, but it is never glaucous-blue. The main veins are very strong and project highly above the surface. The pubescence is arranged in the form of cobwebby tufts or stiff hairs on the veins and their ramifications; it can be colored bluish-white or an intense rust-red.
  • Petiole: long, sturdy, and departs from the leaf blade at an obtuse angle. The surface of the petiole is often covered with short stiff hairs in the form of a small brush or bears flocculent rusty down.

Anatomical Features (according to M. Gard)

Microscopic examination of the internal tissues of the leaf reveals the following specific features of the species: the cells of the lower epidermis of the leaf blade are highly convex (dome-shaped), with the stomata located in depressions below the plane of these cells. The spongy parenchyma has very small intercellular spaces. The bundles of pericyclic fibers in the stem are characterized by large dimensions and wide internal cavities; the medullary ray cells also have a significant volume.

Parameters of Clusters, Berries, and Seeds

  • Cluster: medium or almost large, cylindrical-elongated in shape, winged, with weakly developed lateral branches. The peduncle is short and strong. The pedicels are strong, relatively long, and terminate in a distinct thickening with verrucose bumps; the pedicel cushion is wide and short, colored a rich dark red.
  • Berries: arranged loosely, not forming great density in the cluster. In size, the berries are medium or small, spherical, dark purple, almost black in color, and covered with an abundant layer of glaucous bloom. The skin is elastic, although it has a relatively large thickness. The flesh is low in meatiness, tender, melting, of a greenish tint, and quite juicy. The must is characterized by a pleasant sweet taste with a slight tart (astringent) acidity.
  • Seeds: 2 to 3 seeds are formed in each berry. The seeds are small or medium, their length ranges from 5 to 7 millimeters, and their width from 3 to 5 millimeters. The shape is elongated, almost cylindrical. The surface of the seed is matte, slightly glossy, and colored a brownish-rusty color. The area of the depressions, the chalaza, the seed raphe, and the beak have a lighter and more glossy coloration. The lateral depressions on the ventral side are weakly expressed and lack clear contours. The beak of the seed is short, thick, and practically not separated from the body of the seed. The chalaza is located on the dorsal side, has a regular rounded shape, is strongly raised, and is surrounded along the perimeter only by a narrow groove. The seed raphe originates sharply from the chalaza, forming a very powerful prominent ridge limited on the sides by narrow grooves; it curves around the base of the seed and continues as a distinct relief line on the dorsal side up to the beak itself (pic. 659-660).

Cultural Significance and History of Use

Pure wild forms of Vitis æstivalis have no practical value for commercial viticulture, neither as rootstocks nor as direct producers, despite their relatively high natural resistance to phylloxera. Cuttings of this species possess an extremely low rooting capacity and respond very poorly to bench and field grafting. The vine is rigidly adapted exclusively to red siliceous or sandy substrates and is completely unsuitable for growing on calcareous soils, where it is instantly affected by lime-induced chlorosis. In modern production, the species has given way to more adaptable American vines and is preserved exclusively in ampelographic botanical collections.