Grape leaves hold distinct characteristics that allow for their identification. Understanding these features can help distinguish different grape varieties, useful for foraging, gardening, or simply observing nature.
Key Features for Identification
Grape leaves possess several features for identification. The overall leaf shape and size provide initial clues, often varying between heart-shaped (cordate) or more rounded forms. Leaves can range from medium to large, typically 4 to 8 inches long and slightly less across.
The number and depth of lobes, which are the projections resembling fingers, are significant. Some leaves have pronounced lobes, while others may have minimal or no lobing, appearing more shield-shaped. The indentations between these lobes are called sinuses. Sinuses can vary greatly in shape and depth, appearing as wide open, U-shaped, V-shaped, or even closed with overlapping lobes.
The type of teeth along the leaf margin also offers distinguishing details. These serrations can be sharply pointed, rounded, or finely toothed. Vein patterns, particularly the primary veins that originate from the petiole, are consistent within varieties. The petiole, which is the slender stem attaching the leaf blade to the shoot, also presents characteristics like its length and hairiness. Additionally, the general texture of the leaf, such as whether it feels fuzzy or smooth, provides further identification cues.
Distinguishing Common Grape Varieties by Leaf
The specific combination of leaf features allows for the differentiation of common grape varieties.
Wild grape species, such as Vitis riparia (riverbank grape), have tough leaves with toothed edges and raised veins on the underside. Their leaves are often cordate or orbicular, palmately lobed, and can be shallowly to deeply lobed, usually with three major lobes. Young leaves may be shiny and hairy, becoming green and hairless on the upper surface as they mature, while the lower surface remains paler with hairs along the major veins. Petioles can be reddish.
Vitis labrusca, or fox grape, has large, thick leaves often with three palmate lobes. The underside is notably fuzzy, covered with whitish to rusty brown woolly hairs. Leaves are 4-8 inches long and oval-cordate, with finely and shallowly dentate margins. They have a somewhat leathery texture, and petioles are often covered with woolly brown hairs when young.
Vitis vinifera, the common European wine grape, has orbicular to suborbicular leaves, often prominently lobed with deep sinuses. They are typically 5-20 cm long and broad, usually with 3 to 5 pointed lobes. Margins are coarsely toothed, and the upper surface is often glossy dark green and hairless, while the underside is light green. Some thin tomentum may be present on the lower surface, especially when young.
Practical Identification Strategies
Effective grape leaf identification involves a systematic approach to observation. It is helpful to examine multiple leaves from the same plant, as variations can occur even within a single vine. For instance, deeper lobes might be found on lower leaves of some varieties. Comparing features such as the number and shape of lobes, the depth and form of sinuses, and the type of teeth along the margins will enhance accuracy.
Observing the plant’s growth habit and location provides additional context. Wild grapes often climb trees and other plants using tendrils, with bark that peels in strips on older vines. Cultivated varieties, like Vitis vinifera, are pruned and trained on support systems. Light and perspective also influence how leaf characteristics appear, so observe leaves under different lighting conditions to reveal subtle details. These combined observations contribute to a more reliable identification.