CHAPTER XVII

GRAPE BOTANY

The grape-grower must know the gross structure and the habits of growth of the plants properly to propagate, transplant, prune and otherwise care for the grape. Certainly he must have knowledge of the several species from which varieties come if he is to know the kinds of grapes, understand their adaptations to soils and climates, their relation to insects and fungi, and their value for table, wine, grape-juice and other purposes. Fortunately, the botany of the grape is comparatively simple. The organs of vine and fruit are distinctive and easily discerned and there are no nearly related plants cultivated for fruit with which the grape can possibly be confused. Botanists, it is true, have dug pitfalls for those who seek exact knowledge as to the names and characters of the many species, but, fortunately, each of the cultivated species constitutes a natural group so distinct that the grape-grower can hardly mistake one for another in either fruit or vine.

Plant Characters and Growth Habits of the Grape

A grape plant is a complex organism with its many separate parts especially developed to do one or a few kinds of work. The part of a plant devoted to one or a group of functions is called an organ. The chief organs of the plant are the root, stem, bud, flower, leaf, fruit and seed. Flowers and leaves, it is true, develop from buds and the seeds are parts of the fruits, but for descriptive purposes the vine may well be divided into the parts named. These chief organs are further divided as follows:

The root.

The roots of some species of the grape are soft and succulent as those of V. vinifera, while the same organs in other species, as in most American grapes, are hard and fibrous. They may also be few or numerous, deep or shallow, spreading or restricted, fibrous or non-fibrous. The structure of the root thus becomes important in distinguishing species.

The stem.

Species of grapes have very characteristic vines. A glance at a vine enables one to tell the European grape from any of the American grapes; so, also, one is able to distinguish most of the American species by the aspect of the vine. Many varieties of any species of grape are readily told by the size and habits of the plant. Size of vine is rather more variable than other gross characters because of the influence of environment, such as food, moisture, light, isolation and pests; yet, size in a plant or the parts of a plant is a very reliable character when proper allowances are made for environment.

The degree of hardiness is a very important diagnostic character in determining both species and varieties of grapes and very largely indicates their value for the vineyard. Thus, the varieties of the European grape are less hardy than the peach, while our American Labruscas and Vulpinas are as hardy as the apple. The range of varieties as to hardiness falls within that of the species, and cultivated varieties hardier than the wild grape are not found. Grapes are designated in descriptions of varieties and species as hardy, half-hardy and tender.

Habit of growth varies but little with changing conditions and is thus an important means of distinguishing species and varieties and not infrequently stamps the variety as fit or unfit for the vineyard. Habit of growth gives aspect to the vine. Thus, a vine may be upright, drooping, horizontal, stocky, straggling, spreading, dense or open. The vine may grow rapidly or slowly and may be long-lived or short-lived; the trunk may be short and stocky or long and slender. These several characters largely determine whether a vine is manageable in the vineyard. Productiveness, age of bearing and regularity of bearing are distinctive characters with cultivated grapes. The care given the vine influences these characters; yet all are helpful in identifying species and varieties and all must be considered by the grape-grower.

Immunity and susceptibility to diseases and insects are most valuable diagnostic characters of species and varieties of grapes. Thus, species differ widely in resistance to phylloxera, the grape-louse, to the grape leaf-hopper, the flea-beetle, berry-moth, root-worm, powdery-mildew, downy-mildew, anthracnose and other insect and fungous troubles of this fruit.

The structure of the bark is an important distinguishing character for some species, but is of little importance in identifying the variety and has no economic value to the fruit-grower. In most species of grapes, the bark has distinct lenticels and on the old wood separates in long thin strips and fibers; but in two species from southeastern North America, the bark bears prominent lenticels and never shreds. Smoothness, color and thickness are other attributes of the bark to be noted.

Canes of different species vary greatly in total length and in length of internodes. They vary also in size, in number and in color, while the shape in some species is quite distinctive, being in some round, in others angular and in still others flattened. The direction of growth in canes, whether sinuous, straight or zigzag, is an important character. Nodes and internodes are indicative characters in some species, being more or less prominent, angular or flattened, while the internodes are long or short.

The diaphragm distinguishes several species of grapes. The cane contains a large pith and this in most species is interrupted by woody tissue, forming a diaphragm at the nodes. In the Rotundifolia grapes the diaphragm is absent, while in several other American species it is very thin and in still others quite thick. The character of the diaphragm is best observed in year-old canes. In studying the diaphragm, notice should be taken also of the pith, which is very variable in size.

Young shoots of the grape offer a ready means of distinguishing species and varieties through their color and the amount and character of the pubescence. Shoots may be glabrous, pubescent or hairy and even spiny.

The tendril is one of the organs most used in determining species and varieties of grapes. In some species, as V. Labrusca, there is a tendril or an inflorescence opposite nearly every leaf, continuous tendrils. All other species have two leaves with a tendril opposite each and a third leaf without a tendril, intermittent tendrils. To study this organ it is necessary to have vigorous, healthy, typical canes. Tendrils may be long or short, stout or slender; simple, bifurcated or trifurcated; or smooth, pubescent or warty.

The number of inflorescences borne by species is an important character in some cases. All species, excepting V. Labrusca, average two inflorescences to a cane, but V. Labrusca may bear from three to six inflorescences, each in the place of a tendril opposite the leaf.

The bud.

Buds of different species of grapes vary greatly in time of opening as they do somewhat in varieties, so that the time the buds begin to swell is a fine mark of distinction. The angle at which the bud stands out from the branch is of some value in determining species. Differences in color, size, shape, position and amount of pubescence of buds must all be noted in describing grapes. The scales of the buds vary more or less in size and in thickness.

The flower.

Fig. 53. The grape flower. I. Opening bud showing the way in which the cap becomes loosened at the base. II. Diagrammatic illustration of grape stamens.

The time of bloom is an easy mark of distinction between several species of grapes and helps to distinguish varieties in a species as well. Most species of grapes bear fertile flowers on one vine and sterile flowers on another and are, therefore, polygamous-diœcious. Sterile vines bear male flowers with abortive pistils so that, while they never produce fruits themselves, they usually assist in fertilizing others. Fertile flowers are capable of ripening fruits without cross-pollination. Vines with female flowers only are seldom found. In most species of the grape, plants with sterile flowers and those with complete flowers are found mixed in the wild state, but usually only the fertile plants have been selected for cultivation. Plants raised from seeds of any of the species, however, furnish many sterile vines.

The degree of fertility of blossoms is also a fine mark of distinction in species and varieties of the grape. Fertile vines are of two kinds in most species. The flowers on one kind are perfect hermaphrodites, while in the other kind the stamens are smaller and shorter than the pistil and eventually bent down and curved under. The two kinds of stamens are shown in Figs. [53] and [54]. These may be called imperfect hermaphrodites since they are seldom as fruitful as the perfect hermaphrodites unless fertilized from another plant. Examined with a microscope, it is found that self-sterile plants usually bear abortive pollen and that the percentage of abortive pollen grains varies greatly in different varieties. The upright or depressed stamen does not always indicate the condition of the pollen, since there are many instances in which upright stamens bear impotent pollen and occasionally the depressed stamens bear perfect pollen.

Fig. 54. Grape flowers. Left, upright stamens of Delaware; right, depressed stamens of Brighton.

The leaf.

The size, shape and color of the leaves are quite distinctive of species and more or less so of varieties, if allowances are made for variation due to environment. The lobing of leaves is a very uniform character in most species, some having lobes and others having entire leaves. The upper surface of the leaf in some species is smooth, glossy and shiny and in others is rough and dull. The lower surface shows similar variations and has, besides, varying amounts of pubescence, down and bloom. In some species the down resembles cobwebs. The number, size and shape of the lobes are important in distinguishing both varieties and species, as are also the petiolar, basal and lateral sinuses. As in most plants, the margins of the leaves, whether serrate, dentate or crenate, are often distinguishing characters. The petiole in different species varies from short to long and from stout to slender. Lastly, the time at which the leaves fall is often a good distinguishing mark.

The fruit.

Of all organs the fruit is most responsive to changed conditions and hence most variable. Yet the fruits furnish most valuable characters for determining both species and varieties. Size, shape, compactness and the number of clusters on a shoot must be noted. Coming to the berry, size, shape, color, bloom, adherence of stigma to the apex and adhesion of fruit to the pedicel are all of value. Difference in adherence of the skin to the pulp separates European from all American grapes. The thickness, toughness, flavor and pigment of the skin have more or less value. The color, firmness, juiciness, aroma and flavor of the flesh, as well as its adherence to seed and skin, are valuable marks in describing grapes. All species and varieties are well distinguished by the time of ripening and by keeping quality. The color of the juice is a plain and certain dividing line between some species and many varieties.

The seed.

Seeds are accounted of much value in determining species. The size and weight of seed differ greatly in different species, as they do also in varieties of any one species. Thus, of native grapes, Labrusca has the largest and heaviest seeds and Vulpina has the smallest seed, while those of Æstivalis are of medium size and weight. The shape and color of seed offer distinguishing marks, while the size, shape and position of the raphe and chalaza furnish very certain marks of distinction in some species.

The Genus Vitis

The genus Vitis belongs to the vine family (Vitaceæ) in which most botanists also put the wood-vines (Ampelopsis), of which Virginia creeper is the best-known plant. The genus Cissus, to which belong many southern climbers, is combined with Vitis by some botanists. Vitis is separated from Ampelopsis and Cissus by marked differences in several organs, of which, horticulturally at least, those in the fruit best serve to distinguish the group. Species of Vitis, with possibly one or two exceptions, bear pulpy edible fruits; species of Ampelopsis and Cissus bear fruits with pulp so scant that the berries are inedible. Vitis is further distinguished as follows: The plants are climbing or trailing, rarely shrubby, with woody stems and mostly with coiling, naked-tipped tendrils. The leaves are simple, palmately lobed, round-dentate or heart-shaped-dentate. The stipules are small, falling early. The flowers are polygamo-diœcious (some plants with perfect flowers, others staminate with at most a rudimentary ovary), five-parted. The petals are separated only at the base and fall off without expanding. The disk is hypogynous with five nectariferous glands which are alternate with the stamens. The berry is globose or ovoid, few-seeded and pulpy. The seeds are pyriform and beak-like at the base.

Species of American Grapes

The number of species of grapes in the world depends on the arbitrary limits set for a species of this fruit, and knowledge of the genus is yet too meager to set these limits with certainty. Indeed, the men who have made grape species have seldom been able to outline the habitats of their groups with much certainty. In habitat, it should be said, grapes are confined almost wholly to temperate and subtropical regions. However, the grape-grower is not much concerned with species of grapes other than those that have horticultural value. Of these, in America, there are now ten more or less cultivated either for fruit or for stocks. The following descriptions of these ten species are adapted from the author's The Grapes of New York, published in 1908 by the state of New York (Chapter IV, pages 107–156).

CONSPECTUS OF CULTIVATED SPECIES OF VITIS

A. Skin of mature berry separating freely from the pulp.

B. Nodes without diaphragms; tendrils simple.

1. V. rotundifolia.
2. V. Munsoniana.

BB. Nodes with diaphragms; tendrils forked.

C. Leaves and shoots glabrous at maturity and without bloom; tendrils intermittent.

D. Leaves thin, light, bright green, generally glabrous below at maturity except perhaps in the axils of the veins with a long or at least a prominent point and usually long and sharp teeth or the edge even-jagged.

E. Leaves broader than long; petiolar sinus usually wide and shallow.

3. V. rupestris.

EE. Leaves ovate in outline; petiolar sinus usually medium to narrow.

4. V. vulpina.

DD. Leaves thick, dull colored or grayish-green, often holding some close, dull pubescence below at maturity, shoots and leaves nearly always more or less pubescent when young; the teeth mostly short.

5. V. cordifolia.
6. V. Berlandieri.

CC. Leaves rusty or white tomentose or glaucous blue below, thick or at least firm.

D. Leaves flocculent or cobwebby or glaucous below when fully grown.

7. V. æstivalis.
8. V. bicolor.

DD. Leaves densely tomentose or felt-like beneath throughout the season; covering white or rusty white.

E. Tendrils intermittent.

9. V. candicans.

EE. Tendrils mostly continuous.

10. V. Labrusca.

AA. Skin and pulp of mature berry cohering. (Old World.)

11. V. vinifera.

1. Vitis rotundifolia, Michx. Muscadine Grape. Bull Grape. Bullet Grape. Bushy Grape. Bullace Grape. Scuppernong. Southern Fox Grape.

Vine very vigorous, sometimes, when without support, shrubby and only three or four feet high; when growing in the shade often sending down aërial roots. Wood hard, bark smooth, not scaling, with prominent warty lenticels; shoots short-jointed, angled, with fine scurfy pubescence; diaphragms absent; tendrils intermittent, simple. Leaves small, broadly cordate or roundish; petiolar sinus wide, shallow; margin with obtuse, wide teeth; not lobed; dense in texture, light green color, glabrous above, sometimes pubescent along veins below. Cluster small (6–24 berries), loose; peduncle short; pedicels short, thick. Berries large, globular or somewhat oblate, black or greenish-yellow; skin thick, tough and with a musky odor; pulp tough; ripening unevenly and dropping as soon as ripe. Seeds flattened, shallowly and broadly notched; beak very short; chalaza narrow, slightly depressed with radiating ridges and furrows; raphe a narrow groove. Leafing, flowering and ripening fruit very late.

The habitat of this species is southern Delaware, west through Tennessee, southern Illinois, southeastern Missouri, Arkansas (except the northwestern portions), to Grayson County, Texas, as a northern and western boundary, to the Atlantic Ocean and the Gulf on the east and south. It becomes rare as one approaches the western limit but is common in many sections of the great region outlined above, being most abundant on sandy, well-drained bottom lands and along river banks and in swampy, thick woodlands and thickets. The climate most suitable for Rotundifolia is that in which cotton grows, and it thrives best in the lower portions of the cotton-belt of the United States.

The fruit of Rotundifolia is very characteristic. The skin is thick, has a leathery appearance, adheres strongly to the underlying flesh and is marked with lenticel-like russet dots. The flesh is more or less tough but the toughness is not localized around the seed as in the case of Labrusca. The fruit and most of the varieties of the species are characterized by a strong, musky aroma and are lacking in sugar and acid. Some varieties yield over four gallons of must to the bushel. Wine-makers are divided in opinion as to its value for wine-making, but at present the most promising outlook for Rotundifolia varieties is as wine, grape-juice and culinary grapes. Rotundifolia does not produce fruit suitable for shipping as dessert grapes chiefly because the berries ripen unevenly and when ripe drop from the cluster. The common method of gathering the fruit of this species is to shake the vines at intervals so that the ripe berries drop on sheets spread below the vines. The juice which exudes from the point where the stem is broken off causes the berries to become smeared and gives them an unattractive appearance. Owing, however, to the tough skin, the berries do not crack as badly as other grapes would under the same conditions, but nevertheless they are not adapted to long-distance shipments. Under reasonably favorable conditions, the vines attain great age and size and when grown on arbors, as they often are, and without pruning, they cover a large area.

Rotundifolia is remarkably resistant to the attacks of all insects and to fungal diseases. The phylloxera do not attack its roots and it is considered as resistant as any other, if not the most resistant of all American species. The vines are grown from cuttings only with difficulty and this prevents the use of this species as a resistant stock. However, under favorable circumstances, and with skillful handling, this is a successful method of propagation. Under unfavorable circumstances, or when only a few vines are desired, it is better to depend on layers. As a stock upon which to graft other vines, this species has not been a success. There is great difficulty in crossing Rotundifolia with other species, but several Rotundifolia hybrids are now on record.

2. Vitis Munsoniana, Simpson. Florida Grape. Everbearing grape. Bird Grape. Mustang Grape of Florida.

Vine slender, usually running on the ground or over low bushes. Canes angular; internodes short; tendrils intermittent, simple. Leaves smaller and thinner than Rotundifolia and rather more circular in outline; not lobed; teeth open and spreading; petiolar sinus V-shaped; both surfaces smooth, rather light green. Cluster with more berries but about the same size as in Rotundifolia. Berry one-third to one-half the diameter, with thinner and more tender skin; black, shining; pulp less solid, more acid and without muskiness. Seeds about one-half the size of those of Rotundifolia, similar in other respects. Leafing, flowering and ripening fruit very late.

The habitat of V. Munsoniana is central and southern Florida and the Florida Keys. It extends south of the habitat of Rotundifolia and blends into this species at their point of meeting. Munsoniana appears to be a variation of Rotundifolia, fitted to subtropical conditions. It is tender, not enduring a lower temperature than zero. In the matter of multiplication, it differs from V. rotundifolia in that it can be propagated readily from cuttings. Like Rotundifolia it is resistant to phylloxera.

3. Vitis rupestris, Scheele. Mountain Grape. Rock Grape. Bush Grape. Sand Grape. Sugar Grape. Beach Grape.

A small, much branched shrub or, under favorable circumstances, climbing. Diaphragm thin; tendrils few, or if present, weak, usually deciduous. Leaves small; young leaves frequently folded on midrib; broadly cordate or reniform, wider than long, scarcely ever lobed, smooth, glabrous on both surfaces at maturity; petiolar sinus wide, shallow; margin coarsely toothed, frequently a sharp, abrupt point at terminal. Cluster small. Berries small, black or purple-black. Seeds small, not notched; beak short, blunt; raphe distinct to indistinct, usually showing as a narrow groove; chalaza pear-shaped, sometimes distinct, but usually a depression only. Leafing, blossoming and ripening early.

This species is an inhabitant of southwestern Texas, extending eastward and northward into New Mexico, southern Missouri, Indiana and Tennessee to southern Pennsylvania and the District of Columbia. Its favorite places are gravelly banks and bars of mountain streams or the rocky beds of dry watercourses. This species is rather variable both in type and growth. It was introduced into France at about the same time as Vulpina, and the French vineyardists selected the most vigorous and healthy forms for grafting stock. These pass under the various names of Rupestris Mission, Rupestris du Lot, Rupestris Ganzin, Rupestris Martin, Rupestris St. George and others. In France, these varieties have given particularly good results on bare, rocky soils with hot, dry exposures. In California, Rupestris does not flourish in dry locations, and as it suckers profusely and does not take the graft as readily as Vulpina and Æstivalis, it is not largely propagated.

The clusters of fruit are small, with berries about the size of a currant and varying from sweet to sour. The berry is characterized by much pigment under the skin. The fruit has a sprightly taste wholly free from any disagreeable foxiness. Rupestris under cultivation is said to be very resistant to rot and mildew of the foliage. The vine is considered hardy in the Southwest. The attention of hybridizers was attracted to this species over thirty years ago, and various hybrids have been produced of great promise for grape-breeding. The root system of Rupestris is peculiar in that the roots penetrate at once deeply into the ground instead of extending laterally as in other species. Like those of Vulpina, the roots are slender, hard and resistant to phylloxera. The species is easily propagated by cuttings. The vines bench-graft readily but are difficult to handle in field grafting.

4. Vitis vulpina, Linn. (V. riparia, Michx.). Winter Grape. River Grape. Riverside Grape. Riverbank Grape. Sweet-scented Grape.

Vine very vigorous, climbing. Shoots cylindrical or angled, usually smooth, slender; diaphragms thin; tendrils intermittent, slender, usually bifid. Leaves with large stipules; leaf-blade large, thin, entire, three- or lower ones often five-lobed; sinuses shallow, angular; petiolar sinus broad, usually shallow; margin with incised, sharply serrate teeth of variable size; light green, glabrous above, glabrous but sometimes pubescent on ribs and veins below. Cluster small, compact, shouldered; peduncle short. Berries small, black with a heavy blue bloom. Seeds two to four, small, notched, short, plump, with very short beak; chalaza narrowly oval, depressed, indistinct; raphe usually a groove, sometimes distinct. Very variable in flavor and time of ripening.

Vulpina is the most widely distributed of any American species of grape. It has been discovered in parts of Canada north of Quebec and from thence southward to the Gulf of Mexico. It is found from the Atlantic coast westward, most botanists say, to the Rocky Mountains. Usually it grows on river banks, on islands or in upland ravines. Vulpina has always been considered of great promise in the evolution of American grapes. It can hardly be said that it has fulfilled expectations, there probably being no pure variety of this species of more than local importance, and the results of hybridizing it with other species have not been wholly successful. Attention was early turned to Vulpina because of the qualities presented by the vine rather than those of the fruit, particularly its hardiness and vigor. However, both of these qualities are rather variable, although it is only reasonable to suppose that in such a widely distributed species, plants found in a certain region would have adapted themselves to the conditions there present; thus, it should be expected that the northern plants would be more hardy than those from the South, and that the western prairie forms would be more capable of resisting drouth than those from humid regions. It is, consequently, impossible to say what conditions best suit this species. It may be said, however, that Vulpina is adapted to a great variety of soils and locations; vines have withstood a temperature of 40 to 60 degrees below zero and they show equal ability in withstanding the injurious effects of high temperatures in the summer. On account of its habit of early blooming, the blossoms sometimes suffer from late frosts in the spring.

While Vulpina is not a swamp grape and is not found growing under swampy conditions, it is fond of water. In the semi-arid regions always, and in humid regions usually, it is found growing along the banks of streams, in ravines, on the islands of rivers and in wet places. It is not nearly so capable of withstanding drouth as Rupestris. Vulpina likes a rather rich soil, but in France has been found to do poorly on limestone land and calcareous marls. The French tell us, however, that this is a characteristic of all our American grapes, and that Vulpina is more resistant to the injurious effects of an excess of lime than either Rupestris or Æstivalis.

The fruit of Vulpina is usually small, there being occasional varieties of medium size or above. The clusters are of medium size and, if judged from the standpoint of number of berries, might frequently be called large. The flavor is usually sharply acid but free from foxiness or any disagreeable wild taste. If eaten in quantity, the acidity is likely to affect the lips and end of the tongue. When the acidity is somewhat ameliorated, as in the case of thoroughly ripe or even over-ripe and shriveled fruit, the flavor is much liked. The flesh is neither pulpy nor solid and dissolves in the mouth and separates readily from the seed. The must of Vulpina is characterized by an average amount of sugar, varying considerably in the fruit from different vines, and by an excess of acid.

Vulpina is very resistant to phylloxera, the roots are small, hard, numerous and branch freely. The roots feed close to the surface and do not seem to be well adapted to forcing their way through heavy clays. Vulpina grows readily from cuttings and makes a good stock for grafting, its union with other species being usually permanent. When Vulpinas were first sent to France to be used as a stock in reconstituting the French vineyards, it was found that many of the vines secured from the woods were too weak in growth to support the stronger-growing Viniferas. On this account the French growers selected the more vigorous forms of the Vulpinas, to which they gave varietal names, as Vulpina Gloire, Vulpina Grand Glabre, Vulpina Schribner, Vulpina Martin and others. With these selected Vulpinas, the graft does not outgrow the stock. Vulpina is less resistant to black-rot than Æstivalis but somewhat more resistant than Labrusca. The foliage is rarely attacked by mildew. One of the chief failings of this species is the susceptibility of the leaves to the attack of the leaf-hopper. The Vulpinas are generally late in ripening; the fruit is better in quality in long seasons and should be left on the vines as late as possible.

5. Vitis cordifolia, Michx. Winter Grape. Frost Grape. Fox Grape. Chicken Grape. Heart-leaved Vitis. Possum Grape. Sour Winter Grape.

Vine very vigorous, climbing. Shoots slender; internodes long, angular, usually glabrous, sometimes pubescent; diaphragms thick; tendrils intermittent, long, usually bifid. Leaves with short, broad stipules; leaf-blade medium to large, cordate, entire or indistinctly three-lobed; petiolar sinus deep, usually narrow, acute; margin with coarse angular teeth; point of leaf acuminate; upper surface light green, glossy, glabrous; glabrous or sparingly pubescent below. Clusters medium to large, loose, with long peduncle. Berries numerous and small, black, shining, little or no bloom. Seeds medium in size, broad, beak short; chalaza oval or roundish, elevated, very distinct; raphe a distinct, cord-like ridge. Fruit sour and astringent and frequently consisting of little besides skins and seeds. Leafing, flowering and ripening fruit very late.

Owing to the fact that Cordifolia and Vulpina have been badly confused, the limits of the habitat of this species are difficult to determine. The best authorities give the northern limit as New York or the Great Lakes. The eastern limit is the Atlantic Ocean and the southern limit, the Gulf of Mexico. It extends westward, according to Engelmann, to the western limits of the wooded portion of the Mississippi Valley in the North, and, according to Munson, to the Brazos River, Texas, in the South. It is found along creeks and river banks sometimes mixed with Vulpina, having about the same soil adaptations as that species. It is a very common species in the middle states and frequently grows on limestone soils, but is not indigenous to such soils.

Cordifolia makes a good stock for grafting, being vigorous and forming a good union with most of our cultivated grapes. It is seldom used for this purpose, however, on account of the difficulty of propagating it by means of cuttings. For the same reason vines of it are seldom found in cultivation.

6. Vitis Berlandieri, Planch. Mountain-Grape. Spanish Grape. Fall Grape. Winter Grape. Little Mountain Grape.

Vine vigorous, climbing; shoots more or less angled and pubescent; pubescence remaining only in patches on mature wood; canes mostly with short internodes; diaphragms thick; tendrils intermittent, long, strong, bifid or trifid. Leaves with small stipules; leaf-blade large, broadly cordate, notched or shortly three-lobed; petiolar sinus rather open, V- or U-shaped, margin with broad but rather shallow teeth, rather dark glossy green above, grayish pubescence below when young; becoming glabrous and even glossy except on ribs and veins, when mature. Clusters large, compact, compound, with long peduncle. Berries small, black, with thin bloom, juicy, rather tart but pleasant tasting when thoroughly ripe. Seeds few, small, short, plump, oval or roundish, with short beak; chalaza oval or roundish, distinct; raphe narrow, slightly distinct to indistinct. Leafing, flowering and ripening fruit very late.

Berlandieri is a native of the limestone hills of southwest Texas and adjacent Mexico. It grows in the same region with V. monticola, but is less restricted locally, growing from the tops of the hills down and along the creek bottoms of these regions. Its great virtue is that it withstands a soil largely composed of lime, being superior to all other American species in this respect. This and its moderate degree of vigor have recommended it to the French growers as a stock for their calcareous soils. The roots are strong, thick, and very resistant to phylloxera. It is propagated by cuttings with comparative ease, but its varieties are variable, some not rooting at all easily. While the fruit of this species shows a large cluster, the berries are small and sour, and Berlandieri is not regarded as having promise for culture in America.

7. Vitis æstivalis, Michx. Blue Grape. Bunch Grape. Summer Grape. Little Grape. Duck-shot Grape. Swamp Grape. Chicken Grape. Pigeon Grape.

Vine very vigorous, shoots pubescent or smooth when young; diaphragms thick; tendrils intermittent, usually bifid. Leaves with short, broad stipules; leaf-blade large, thin when young but becoming thick; petiolar sinus deep, usually narrow, frequently overlapping; margin rarely entire, usually three- to five-lobed; teeth dentate, shallow, wide; upper surface dark green; lower surface with more or less reddish or rusty pubescence which, in mature leaves, usually shows in patches on the ribs and veins; petioles frequently pubescent. Clusters long, not much branched, with long peduncle. Berries small, with moderate amount of bloom, usually astringent. Seeds two to three, of medium size, plump, smooth, not notched; chalaza oval, distinct; raphe a distinct cord-like ridge. Leafing and ripening fruit late to very late.

The division of the original species has reduced the habitat materially, confining it to the southeastern part of the United States from southern New York to Florida and westward to the Mississippi River. Æstivalis grows in thickets and openings in the woods and shows no such fondness for streams as Vulpina, or for thick timber as Labrusca, but is generally confined to uplands. Under favorable circumstances, the vines grow to be very large. Æstivalis is preëminently a wine grape. The fruit usually has a tart, acrid taste, due to the presence of a high percentage of acid, but there is also a large amount of sugar, the scale showing that juice from this species has a much higher percentage of sugar than the sweeter-tasting Labruscas. The wine made from varieties of Æstivalis is very rich in coloring matter and is used by some European vintners to mix with the must of European sorts in order to give the combined product a higher color. The berries are destitute of pulp, have a comparatively thin, tough skin and a peculiar spicy flavor. The berries hang to the bunch after becoming ripe much better than do those of Labrusca.

This species thrives in a lighter and shallower soil than Labrusca and appears to endure drought better, although not equaling in this respect either Vulpina or Rupestris. The French growers report that Æstivalis is very liable to chlorosis on soils which contain much lime. The leaves are never injured by the sun and they resist the attacks of insects, such as leaf-hoppers, better than any other American species under cultivation. Æstivalis is rarely injured by black-rot or mildew, according to American experience, but French growers speak of its being susceptible to both. The hard roots of Æstivalis enable it to resist phylloxera, and varieties with any great amount of the blood of this species are seldom seriously injured by this insect. An objection to Æstivalis, from a horticultural standpoint, is that it does not root well from cuttings. Many authorities speak of it as not rooting at all from cuttings, but this is an over-statement of the facts, as many of the wild and cultivated varieties are occasionally propagated in this manner, and some southern nurseries, located in particularly favorable situations, make a practice of propagating it by this method. Varieties of this species bear grafting well, especially in the vineyard.

Vitis æstivalis Lincecumii, Munson. Post-oak Grape. Pine-wood Grape. Turkey Grape.

Vine vigorous, sometimes climbing high upon trees, sometimes forming a bushy clump from two to six feet high; canes cylindrical, much rusty wool on shoots; tendrils intermittent. Leaves very large, almost as wide as long; entire or three-, five-, or rarely seven-lobed; lobes frequently divided; sinuses, including petiolar sinus, deep; smooth above, and with more or less rusty pubescence below. (The north-Texas, southwestern Missouri and northern Arkansas form shows little or no pubescence but has fine prickly spines at base of shoots and shows much blue bloom on shoots, canes and the under side of the leaves.) Fruit small to large, usually larger than typical Æstivalis, usually black, with heavy bloom. Seeds larger than Æstivalis, pear-shaped; chalaza roundish.

Lincecumii inhabits the eastern half of Texas, western Louisiana, Oklahoma, Arkansas and southern Missouri on high sandy land, frequently climbing post-oak trees, hence the name, post-oak grape, by which it is locally known.

Lincecumii has attracted considerable attention through the work of H. Jaeger and T. V. Munson in domesticating it, both of whom considered it one of the most, if not the most, promising form from which to secure cultivated varieties for the Southwest. The qualities which recommend it are: First, vigor; second, capacity to withstand rot and mildew; third, hardiness and capacity to endure hot and dry summers without injury; fourth, the large cluster and berry which were found on certain of the wild vines. The fruit is characteristic because of its dense bloom, firm, yet tender texture and peculiar flavor. The cultivated varieties have given satisfaction in many sections of the Central Western and Southern states. Like Æstivalis, it is difficult to propagate from cuttings.

The north-Texas glaucous form of this variety mentioned in the technical description above is the V. æstivalis glauca of Bailey. This is the type of Lincecumii that Munson has used in breeding work.

Vitis æstivalis Bourquiniana, Bailey. Southern Æstivalis.

Bourquiniana differs chiefly from the type in having thinner leaves; the shoots and under side of the leaves are only slightly reddish-brown in color; the pubescence usually disappears at maturity; the leaves are more deeply lobed than is common in Æstivalis; and the fruit is larger, sweeter and more juicy. Bourquiniana is known only in cultivation. The name was given by Munson, who ranks the group as a species. He includes therein many southern varieties, the most important of which are: Herbemont, Bertrand, Cunningham and Lenoir, grouped in the Herbemont section; and Devereaux, Louisiana and Warren, in the Devereaux section. Munson has traced the history of this interesting group and states that it was brought from southern France to America over one hundred fifty years ago by the Bourquin family of Savannah, Georgia. Many botanists are of the opinion that Bourquiniana is a hybrid. The hybrid supposition is corroborated to a degree by the characters being more or less intermediate between the supposed parent species, and also by the fact that up to date no wild form of Bourquiniana has been found. The only northern variety of any importance supposed to have Bourquiniana blood is the Delaware, and in this variety only a fraction of Bourquiniana blood is presumably present. Bourquiniana can be propagated from cuttings more easily than the typical Æstivalis but not so readily as Labrusca, Vulpina or Vinifera. Many of the varieties of Bourquiniana show a marked susceptibility to mildew and black-rot; in fact, the whole Herbemont group is much inferior in this respect to the Norton group of Æstivalis. The roots are somewhat hard, branch rather freely and are quite resistant to phylloxera.

8. Vitis bicolor, Le Conte. Blue Grape. Northern Summer Grape. Northern Æstivalis.

Vine vigorous, climbing; shoots cylindrical or angled, with long internodes, generally glabrous, usually showing much blue bloom, sometimes spiny at base; diaphragms thick; tendrils intermittent, long, usually bifid. Leaves with short, broad stipules; leaf-blade large; roundish-cordate, usually three-, sometimes on older growth shallowly five-lobed, rarely entire; petiolar sinus variable in depth, usually narrow; margin irregularly dentate; teeth acuminate; glabrous above, usually glabrous below and showing much blue bloom which sometimes disappears late in the season; young leaves sometimes pubescent; petioles very long. Cluster of medium size, compact, simple; peduncle long. Berries small, black with much bloom, acid but pleasant tasting when ripe. Seeds small, plump, broadly oval, very short beak; chalaza oval, raised, distinct; raphe distinct, showing as a cord-like ridge.

Bicolor is readily distinguished from Æstivalis by the absence of the reddish pubescence and by blooming slightly later. The habitat of Bicolor is to the north of that of Æstivalis, occupying the northeastern, whereas Æstivalis occupies the southeastern quarter of the United States. Like Æstivalis, this species is not confined to streams and river banks but frequently grows on higher land also. It is found in north Missouri, Illinois, southwestern Wisconsin, Indiana, southern Michigan, Ohio, Kentucky, Pennsylvania, New York, southwestern Ontario, New Jersey and Maryland and by some botanists is reported as far south as western North Carolina and west Tennessee.

The horticultural characters of Bicolor are much the same as those of Æstivalis. About the only points of difference are that it is much hardier (some of the Wisconsin vines stand a temperature as low as 20 degrees below zero); it is said to be slightly less resistant to mildew and more resistant to phylloxera. Like Æstivalis, Bicolor does not thrive on limy soils and it is difficult to propagate from cuttings. The horticultural possibilities of Bicolor are probably much the same as those of Æstivalis, although many think it to be more promising for the North. It is as yet cultivated but little. Its chief defect for domestication is the small size of the fruit.

9. Vitis candicans, Englem. Mustang Grape.

Vine very vigorous, climbing; shoots and petioles densely wooly, whitish or rusty; diaphragm thick; tendrils intermittent. Leaves with large stipules; blade small, broadly cordate to reniform-ovate, entire or in young shoots and on young vines and sprouts usually deeply three- to five-, or even seven-lobed; teeth shallow, sinuate; petiolar sinus shallow, wide, sometimes lacking; dull, slightly rugose above, dense whitish pubescence below. Clusters small. Berries medium to large, black, purple, green, or even whitish, thin blue bloom or bloomless. Seeds usually three or four, large, short, plump, blunt, notched; chalaza oval, depressed, indistinct; raphe a broad groove.

The habitat of this grape extends from southern Oklahoma, as a northern limit, southwesterly into Mexico. The western boundary is the Pecos River. It is found on dry, alluvial, sandy or limestone bottoms or on limestone bluff lands and is said to be especially abundant along upland ravines. Candicans grows well on limestone lands, enduring as much as 60 per cent of carbonate of lime in the soil. The species blooms shortly before Labrusca and a week later than Vulpina. It requires the long hot summers of its native country and will stand extreme drouth but is not hardy to cold, 10 or 15 degrees below zero killing the vine outright unless protected; and a lesser degree of cold injuring it severely. The berries, which are large for wild vines, have thin skins under which there is a pigment which gives them, when first ripe, a fiery, pungent taste but which partly disappears with maturity. The berries are very persistent, clinging to the pedicel long after ripe. Candicans is difficult to propagate from cuttings. Its roots resist phylloxera fairly well. It makes a good stock for Vinifera vines in its native country, but owing to the difficulty of propagation is seldom used for that purpose. In the early days of Texas, it was much used for the making of wine but as it is deficient in sugar, and as the must retains the acrid, pungent flavor, it does not seem to be well adapted for this purpose. It is not regarded as having great promise for southern horticulture and certainly has none for the North.

10. Vitis Labrusca, Linn. Fox-Grape.

Vine vigorous, stocky, climbing; shoots cylindrical, densely pubescent; diaphragms medium to thick; tendrils continuous, strong, bifid or trifid. Leaves with long, cordate stipules; leaf-blade large, thick, broadly cordate or round; entire or three-lobed, frequently notched; sinuses rounded; petiolar sinus variable in depth and width, V-shaped; margin with shallow, acute-pointed, scalloped teeth; upper surface rugose, dark green, on young leaves pubescent, becoming glabrous when mature; lower surface covered with dense pubescence, more or less whitish on young leaves, becoming dun-colored when mature. Clusters more or less compound, usually shouldered, compact; pedicels thick; peduncle short. Berries round; skin thick, covered with bloom, with strong musky or foxy aroma. Seeds two to four, large, distinctly notched, beak short; chalaza oval in shape, indistinct, showing as a depression; raphe, a groove.

Labrusca is indigenous to the eastern part of North America, including the region between the Atlantic Ocean and the Alleghany Mountains. It is sometimes found in the valleys and along the western slopes of the Alleghanies. Many botanists say it never occurs in the Mississippi Valley. In the first-named area it ranges from Maine to Georgia. It has the most restricted habitat of any American species of horticultural importance, being much exceeded in extent of territory by V. rotundifolia, V. æstivalis and V. vulpina.

Labrusca has furnished more cultivated varieties, either pure-breeds or hybrids, than all other American species together. The reason for this is partly, no doubt, that it is native to the portion of the United States first settled and is the most common grape in the region where agriculture first advanced to the condition at which fruits were desired. This does not wholly account for its prominence, however, which must be sought elsewhere. In its wild state, Labrusca is probably the most attractive to the eye of any of our American grapes on account of the size of its fruit, and this undoubtedly turned the attention of those who were early interested in the possibilities of American grape-growing to this species rather than to any other.

The southern Labrusca is quite different from the northern form and demands different conditions for its successful growth; in the North, at least two types of the species may be distinguished. Vines are found in the woods of New England which resemble Concord very closely in both vine and fruit, excepting that the grapes are much smaller in size and more seedy. There is also the large-fruited, foxy Labrusca, usually with reddish berries, represented by such cultivated varieties as Northern Muscadine, Dracut Amber, Lutie and others. Labrusca is peculiar amongst American grapes in showing black-, white- and red-fruited forms of wild vines growing in the woods. Because of this variability, it is impossible to give the exact climatic and soil conditions best adapted to the species. It is reasonable to suppose, however, that the ideal conditions for this species under cultivation are not widely different from those prevailing where the species is indigenous. In the case of Labrusca, this means that it is best adapted to humid climates, and that the temperature desired varies according to whether the variety comes from the southern or northern form of the species.

The root system of Labrusca does not penetrate the soil deeply, but the vine is said to succeed better in deep and clayey soils than Æstivalis. It endures an excess of water in the soil, and, on the other hand, requires less water for successful growing than Æstivalis or Vulpina. In spite of its ability to withstand clayey soils, it seems to prefer loose, warm, well-drained sandy lands to all others. The French growers report that all varieties of this species show a marked antipathy to a limestone soil, the vines soon becoming affected with chlorosis when planted in soils of this nature. In corroboration of this, it may be said that Labrusca is not often found wild in limestone soils. The Labruscas succeed very well in the North and fairly well in the Middle West as far south as Arkansas, where they are raised on account of their fruit qualities, for here the vines are not nearly so vigorous and healthy as are those of other species. In Alabama, they are reported to be generally unsatisfactory, and in Texas the vines are short-lived, unhealthy, and generally unsatisfactory, particularly in the dry regions. There are some exceptions to this, as for instance, in the Piedmont region of the Carolinas, where, owing to elevation or other causes, the climate of a southern region is semi-northern in its character.

The grapes of Labrusca are large and usually handsomely colored. The skin is thick, covering a layer of adhering flesh, which gives the impression of its being thicker than it actually is; the berry is variable in tenderness, sometimes tough, but in many cultivated varieties is so tender that it cracks in transportation. The skin of this species usually has a peculiar aroma, generally spoken of as foxy, and a slightly acid, astringent taste. Beneath the skin there is a layer of juicy pulp, quite sweet and never showing much acidity in ripe fruit. The center of the berry is occupied by rather dense pulp, more or less stringy, with considerable acid close to the seeds. Many object to the foxy aroma of this species, but, nevertheless, the most popular American varieties are more or less foxy. Analyses show that the fruit is usually characterized by a low percentage of sugar and acid, the very sweet-tasting fox-grapes not showing as high a sugar-content as some of the disagreeably tart Æstivalis and Vulpina sorts. This, in addition to the foxiness which furnishes an excess of aroma in the wine, has prevented Labrusca varieties from becoming favorites with the wine-makers, but most of the grape-juice now manufactured is made from them.

In addition to the characters enumerated, it may be said that Labrusca submits well to vineyard culture, is fairly vigorous and generally quite productive. It grows readily from cuttings and in hardiness is intermediate between Vulpina, the hardiest of our American species, and Æstivalis. The roots are soft and fleshy (for an American grape) and in some localities subject to attacks of phylloxera. None of the varieties of Labrusca has ever been popular in France on this account. In the wild vines, the fruit is inclined to drop when ripe. This defect is known as "shattering" or "shelling" among grape-growers and is a serious weakness in some varieties. Labrusca is said to be more sensitive in its wild state to mildew and black-rot than any other American species, but the evidence on this point does not seem to be wholly conclusive. In the South, and in some parts of the Middle West, the leaves of all varieties of Labrusca sunburn and shrivel in the latter part of the summer. The vines do not endure drouth as well as Æstivalis or Vulpina and not nearly so well as Rupestris.

11. Vitis vinifera, Linn.

Vine variable in vigor, not so high climbing as most American species; tendrils intermittent. Leaves round-cordate, thin, smooth, and when young, shining, frequently more or less deeply three-, five-, or even seven-lobed; usually glabrous but in some varieties the leaves and young shoots are hairy and even downy when young; lobes rounded or pointed; teeth variable; petiolar sinus deep, narrow, usually overlapping. Berries very variable in size and color, usually oval though globular. Seeds variable in size and shape, usually notched at upper end and characterized always by a bottle-necked, elongated beak; chalaza broad, usually rough, distinct; raphe indistinct. Roots large, soft and spongy.

The original habitat of the species is not positively known. De Candolle, as noted in the first part of this work, considered the region about the Caspian Sea as the probable habitat of the Old World grape. There is but little doubt that the original home of V. vinifera is some place in western Asia.

Neither American nor European writers agree as to the climate desired by Vinifera, for the reason, probably that all of the varieties in this variable species do not require the same climatic conditions. There are certain phases of climate, however, that are well agreed on: the species requires a warm, dry climate and is more sensitive to change of temperature than American species. Varieties of this species can be grown successfully in a wide variety of soils, being much less particular as to soils than American sorts.

Certain characters of the fruit of this species are not found in any American forms: First, the skin, which is attached very closely to the flesh and which is never astringent or acid, can be eaten with the fruit; second, the flesh is firm, yet tender, and uniform throughout, differing in this respect from all American grapes which have a sweet, watery and tender pulp close to the skin with a tough and more or less acid core at the center; third, the flavor has a peculiarly sprightly quality known as vinous; fourth, the berry adheres firmly to the pedicel, the fruit seldom "shattering" or "shelling" from the cluster.

In the various hybrids that have been made between American and Vinifera varieties, it is usually found that the desirable qualities of Vinifera are inherited in about the same proportion as the undesirable ones. The fruit is improved in the hybrid but the vine is weakened; quality is usually purchased at the expense of hardiness and disease-resisting power. Vinifera may be grown very readily from cuttings.

Plate XXIII.—Lutie (×1/2). Pocklington (×1/2).