Southwest Desert Flora

The Rosaceae or Rose family is large and diverse containing over 100 genera and more than 4,800 accepted species names. Other local names are Mountain Mahogany, Hawthorn, Serviceberry and Strawberry. Species numbers vary between authorities and Southwest Desert Flora uses The Plant List which creates taxonomic data through collaboration between the Royal Botanic Gardens, Kew, the Missouri Botanical Garden and other institutions.

The Rose family was split into 4 sub-families according to their floral and fruit arrangements. However, currently with molecular applications previous classifications were changed and additional changes are underway. Rosaceae are worldwide in a wide variety of habitats with greatest diversities in the Northern Hemisphere in temperate zones. Rosaceae are mostly absent from hot deserts and low-altitude tropics. Family species include herbs, shrubs and trees.

Some of the largest genera worldwide include Alchemilla, Sorbus, Crataegus, Cotoneaster, Rubus, and Prunus. In North America the largest genera include Rubus, Crataegus, Rosa, Potentilla, Cotoneaster and Prunus.

Common family characteristics: Rosaceae characteristics vary across a wide spectrum of specialized forms including the inflorescence, leaves and flora parts. Most species are woody shrubs and trees but a few are herbaceous perennial plants such as wild strawberries (Fragaria) and Cinquefoil (Potentilla). Most are glabrous and have spiny or thorny armament preventing animals from eating the plants and at the same time provides security and protection for birds and small mammals.

Leaves: Leaves are mostly alternate; simple or compound; persistent or deciduous; stipules may be present; margins serrate. Inflorescences: Much variation in the inflorescence including a range of panicles, racemes, corymbs, cymes and solitary flowers. Flowers: Flowers usually bisexual, rarely unisexual; often large and showy, others small; flower colors variable and include red, pink, yellow, orange and lavender; flowers usually radially symmetrical; actinomorphic; sepals and petals 4 or 5; numerous stamens; many have a characteristic fundamentally saucer-shaped hypanthium. Considerable variation in flowers and fruits. Fruit: fruits achenes, follicles, drupes, nutlets, pomes or capsules. Type of fruit is a basis to determine the sub-family.

Plants of economic importance: The Rosaceae Family is not be the largest family but provides significant economic value worldwide in food and cultivated ornamentals. Included in the family are such important fruits as; strawberries, blackberries,raspberries, apples, peach, pears, quinces, plums, cherries, peaches, apricots, and almonds. Cultivated ornamentals are beautiful natural plants include the beautiful and highly valued roses of the genus Rosa. Other beautiful cultivated plants include; the genus Photinia cultivated for their beautiful red and white flowers; Filipendula beautiful multicolored flowers; Pyracantha or Firethorns, with beautiful red berries in the fall and other showy ornamentals such as Sorbus, Rhaphiolepis and Crataegus.

In Arizona, many of the Rosaceae species provide important browse for deer and livestock. The flowers provide nectar for insects and the fruits provide food for birds and mammals.