Many fruits of the family are edible, but their seeds often contain amygdalin, which can release cyanide during digestion if the seed is damaged. They can be follicles, capsules, nuts, achenes, drupes ( Prunus), and accessory fruits, like the pome of an apple, or the hip of a rose. The fruits occur in many varieties and were once considered the main characters for the definition of subfamilies amongst Rosaceae, giving rise to a fundamentally artificial subdivision. Rosaceae have a variety of color petals, but blue is almost completely absent. They can be arranged in spikes, or heads. The bases of the sepals, petals, and stamens are fused together to form a characteristic cup-like structure called a hypanthium. Rosaceae generally have five sepals, five petals, and many spirally arranged stamens. They are radially symmetrical, and almost always hermaphroditic. Spines may be present on the midrib of leaflets and the rachis of compound leaves.įlowers of plants in the rose family are generally described as "showy". Glands or extrafloral nectaries may be present on leaf margins or petioles. The stipules are sometimes adnate (attached surface to surface) to the petiole. Paired stipules are generally present, and are a primitive feature within the family, independently lost in many groups of Amygdaloideae (previously called Spiraeoideae). Compound leaves appear in around 30 genera. They can be simple or pinnately compound (either odd- or even-pinnate). The leaves are generally arranged spirally, but have an opposite arrangement in some species. The herbs are mostly perennials, but some annuals also exist. Rosaceae can be woody trees, shrubs, climbers or herbaceous plants. The family also includes popular ornamental trees and shrubs, such as roses, meadowsweets, rowans, firethorns, and photinias. Many economically important products come from the Rosaceae, including various edible fruits, such as apples, pears, quinces, apricots, plums, cherries, peaches, raspberries, blackberries, loquats, strawberries, rose hips, hawthorns, and almonds. They have a worldwide range but are most diverse in the Northern Hemisphere. Most species are deciduous, but some are evergreen. The family Rosaceae includes herbs, shrubs, and trees. However, all of these numbers should be seen as estimates-much taxonomic work remains. Among the most species-rich genera are Alchemilla (270), Sorbus (260), Crataegus (260), Cotoneaster (260), Rubus (250), and Prunus (200), which contains the plums, cherries, peaches, apricots, and almonds. The name is derived from the type genus Rosa.
Rosaceae ( / r oʊ ˈ z eɪ s iː ˌ iː, - s i ˌ aɪ/), the rose family, is a medium-sized family of flowering plants that includes 4,828 known species in 91 genera. Potentillaceae Sprengel ex Weinmann 1824.
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