Rosaceae (), the rose family, is a family of flowering plants that includes 4,828 known species in 91 genera.
The name is derived from the type genus Rosa. The family includes herbs, shrubs, and trees. Most species are deciduous, but some are evergreen. They have a worldwide range but are most diverse in the Northern Hemisphere.
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. The family also includes popular ornamental trees and shrubs, such as roses, meadowsweets, rowans, firethorns, and photinias. However, all of these numbers should be seen as estimates—much taxonomic work remains.
Description
Rosaceae can be woody trees, shrubs, climbers or herbaceous plants. The herbs are mostly perennials, but some annuals also exist, such as Aphanes arvensis.
Leaves
The leaves are generally arranged spirally, but have an opposite arrangement in some species. They can be simple or pinnately compound (either odd- or even-pinnate). Compound leaves appear in around 30 genera. The leaf margin is most often serrate. Paired stipules are generally present and are considered a primitive feature within the family, though they have been independently lost in many groups of Amygdaloideae (previously called Spiraeoideae). to the petiole. Glands or extrafloral nectaries may be present on leaf margins or petioles. Spines may be present on the midrib of leaflets and the rachis of compound leaves.
Flowers
Flowers of plants in the rose family are generally described as "showy". They are radially symmetrical, and almost always hermaphroditic. Rosaceae 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 called a hypanthium. They can be arranged in spikes, or heads. Solitary flowers are rare. Rosaceae have a variety of color petals, but blue is almost completely absent.
Taxonomy
Taxonomic history
The family was traditionally divided into six subfamilies: Rosoideae, Spiraeoideae, Maloideae (Pomoideae), Amygdaloideae (Prunoideae), Neuradoideae, and Chrysobalanoideae, and most of these were treated as families by various authors. Later (1971), Chrysobalanoideae was placed in Malpighiales and Neuradoideae has been assigned to Malvales. Schulze-Menz, in Engler's Syllabus edited by Melchior (1964), recognized Rosoideae, Dryadoideae, Lyonothamnoideae, Spireoideae, Amygdaloideae, and Maloideae. They were primarily diagnosed by the structure of the fruits. More recent work has identified that not all of these groups were monophyletic. Hutchinson (1964) and Kalkman (2004) recognized only tribes (17 and 21, respectively). Takhtajan (1997) delimited 21 tribes in 10 subfamilies: Li et al. (2015), Li et al. (2016), and Sun et al. (2016). Most recently Zhang et al. (2017) recovered these relationships using whole plastid genomes:
The sister relationship between Dryadoideae and Rosoideae is supported by the following shared morphological characters not found in Amygdaloideae: presence of stipules, separation of the hypanthium from the ovary, and the fruits are usually achenes. and Potter (2003). Most recently Xiang et al. (2017) recovered these relationships using nuclear transcriptomes:
Rosoideae basal
Rosoideae has been identified as the earliest branching subfamily by Morgan et al. (1994), Evans (1999), Potter et al. (2002), Potter et al. (2007), Töpel et al. (2012), and Chen et al. (2016). The following is taken from Potter et al. (2007): and includes apples, pears, quinces, medlars, loquats, almonds, peaches, apricots, plums, cherries, strawberries, blackberries, raspberries, sloes, and roses.
Many genera are also highly valued ornamental plants. These include trees and shrubs (Aronia, Cotoneaster, Chaenomeles, Crataegus, Dasiphora, Exochorda, Kerria, Photinia, Physocarpus, Prunus, Pyracantha, Rhodotypos, Rosa, Sorbus, Spiraea), herbaceous perennials (Alchemilla, Aruncus, Filipendula, Geum, Potentilla, Sanguisorba), alpine plants (Dryas, Geum, Potentilla) and climbers (Rosa).