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 AEstivalis 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 (Vitaceae) 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-dioecious (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