THE ROSE FAMILY (Rosaceae)

This is a medium-sized family of flowering plants, including about 2830 species. The name is derived from the type genus Rosa but the largest genus by far is Prunus (plums, cherries, peaches, apricots and almonds) with about 430 species. Roses can be herbs, shrubs or trees. Most species are deciduous, but some are evergreen. They have a worldwide range, but are most diverse in temperate zones of the northern hemisphere.

Several economically important products come from Rosaceae, including many edible fruits (apples, pears, quinces, apricots, plums, cherries, peaches, raspberries, and strawberries), almonds, ornamental trees and shrubs (roses, meadowsweets, firethorns, rowans, and hawthorns)

The leaves are generally arranged spirally, but have an opposite arrangement in some species. They can be simple or pinnately compound. Paired stipules (secondary leaflets growing out from the base of the leaf stem) are generally present and are a primitive feature within the family. Glands or extrafloral nectaries may be present on leaf margin or petiole. Spines may be present on the midrib of leaflets and the rachis (main vein) of compound leaves.

Flowers of plants in the rose family are generally described as "showy".[5] They are actinomorphic (i.e. radially symmetrical). They generally have five sepals, five petals and many spirally arranged stamens. The bases of the sepals, petals, and stamens are fused together to form a characteristic cup-like structure. They can be carried in spikes, heads or branched arrangements; solitary flowers are rare.

The fruits come in many varieties and were once considered the main characters for the definition of subfamilies amongst Rosaceae. They can be follicles, capsules, nuts, dry achenes, fleshy drupes (Prunus) and accessory fruits, like the pome of an apple, or the hip of a rose.

(source: Wikipedia)