Fig. 54. Grape flowers. Left, upright stamens of Delaware; right, depressed stamens of Brighton.
The leaf.
- Blade: The expanded portion of the leaf.
- Lobe: The more or less rounded division of the leaf.
- Sinus: The recess or bay between two lobes.
- Petiole: The leaf-stalk.
- Petiolar sinus: The sinus about the petiole.
- Basal sinuses: The two sinuses toward the base of the blade.
- Lateral sinuses: The two sinuses toward the apex of the blade.
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.
- Peduncle and pedicel: Defined as in flower.
- Brush: The end of the pedicel projecting into the fruit.
- Base: The point of attachment of bunch or berry.
- Apex: The point opposite the base.
- Bloom: The powdery coating on the fruit.
- Pigment: The coloring matter in the skin.
- Quality: The combination of characters that makes grapes pleasant to the palate, sight, smell and touch.
- Foxiness: The rancid taste and smell of some grapes which are similar to the effluvium of a fox.
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.