Vitis (grapevines) is a genus of about 60 species of vining plants in the flowering plant family Vitaceae. The genus is made up of species predominantly from the Northern hemisphere. It is economically important as the source of grapes, both for direct consumption of the fruit and for fermentation to produce wine. The study and cultivation of grapevines is called viticulture.All vines share the same basic, physiological features. The roots anchor the vine to the soil and serve as the conduit where nutrients and water from the soil are absorbed. Along with the trunk or "permanent wood" features, the roots also serve as storage reserve of carbohydrates which the vine can use for energy in the winter after the leaves have fallen and are no longer conducting photosynthesis. The function of photosynthesis in the grapevine is to produce glucose which can be combined with other molecules to form larger carbohydrates (such as cellulose) that can be used to create other structures in the vine, energy reserves for the plant and, for fruiting grapevines, can be concentrated in grape berries which contain the reproductive seeds of the vine and are more attractive to birds and other animals.Other parts of the grapevine include the tendrils which the vine uses to support itself by clinging to surrounding structures (such as the trellising of a vine-training system) and the shoots which sprout from the permanent wood and contain nodes where new leaves, flowers and tendrils can form. At the joint where leaves connect to the shoot are buds or "embryonic shoots" that contain the structures that will grow into the following years shoots, tendrils, flowers and leaves.Most Vitis varieties are wind-pollinated with hermaphroditic flowers containing both male and female reproductive structures. These flowers are grouped in bunches called inflorescences. In many varieties, such as Vitis vinifera, each successfully pollinated flower becomes a grape berry with the inflorescence turning into a cluster of grapes. While the flowers of the grapevines are usually very small, the berries are often big, brightly colored with sweet flavors that attract birds and animals to disperse the seeds contained within the berries.Grapevines usually only produce fruit on shoots that came from buds that were developed during the previous growing season. In viticulture, this is one of the principles behind pruning the previous years growth (or "One year old wood") that includes shoots that have turned hard and woody during the winter (after harvest in commercial viticulture). These vines will be pruned either into a cane which will support 8 to 15 buds or to a smaller spur which holds 2 to 3 buds.