A subclass of the dicotyledons containing both woody and herbaceous species. Its members usually have bisexual flowers that often contain numerous stamens, which develop centripetally. The Rosidae may contain some 14-21 orders depending on the classification scheme referred to. The inclusion of the following 13 orders is generally agreed: Rosales, including the *Rosaceae
; Fabales, including the *Leguminosae
; Myrtales, including the Rhizophoraceae (e.g. mangroves) and Myrtaceae; Proteales; Podostemales; Santalales, including the Santalaceae (e.g. sandalwoods); Celastrales, including the Celastraceae (e.g. spindle tree) and Aquifoliaceae (e.g. hollies); Rhamnales, including the Rhamnaceae (e.g. buckthorns) and Vitaceae (e.g. grape vines); Sapindales, including the Sapindaceae (e.g. soapberries), Hippocastanaceae (e.g. horse chestnuts), and Aceraceae (maples); Geraniales, including the Geraniaceae, Oxalidaceae (e.g. wood sorrels), and Balsaminaceae; Polygalales; Umbellales (or Cornales), including the Araliaceae (e.g. ivies) and *Umbelliferae
; and Haloragales (or Hippuridales).
In addition, the following four orders may be recognized but these are often included in other orders of the Rosidae: Saxifragales, including the Crassulaceae (e.g. stonecrops) and Saxifragaceae, often placed in the Rosales; Connarales (e.g. zebra woods), and Rutales, including the Rutaceae (citrus family), Meliaceae (e.g. mahogonies), and Anacardiaceae (e.g. cashews), both often placed in the Sapindales; and Elaeagnales, containing the Elaeagnaceae (e.g. oleasters), often placed in the Proteales.
Some classifications include the Rafflesi-ales (often placed in the Magnoliidae) and the Juglandales (often placed in the Hamamelidae) in the Rosidae. The order Oleales, including the Oleaceae (e.g. olives, lilacs), is often seen in the order Gentianales of the subclass Asteridae. The Euphorbiales, including the *Euphorbiaceae
(spurge family), is sometimes classified in the Dilleniidae. Finally the two families Droseraceae (e.g. sundews) and Nepenthaceae (pitcher plants) making up the order Nepenthales are sometimes split and allocated to the Rosales and Aristolochiales (subclass Magnoliidae) respectively.