Rosaceae - Genera

Genera

Identified clades include:

• Subfamily Rosoideae: Traditionally composed of those genera bearing aggregate fruits that are made up of small achenes or drupelets, and often the fleshy part of the fruit (e.g. Strawberry) is the receptacle or the stalk bearing the carpels. The circumscription is now narrowed (excluding, for example, the Dryadoideae), but it still remains a diverse group containing 5 or 6 tribes and 20 or more genera, including Rose, blackberry, raspberry, strawberry, Potentilla, Geum.
• Subfamily Maloideae (or Pomoideae): Traditionally this included only those genera (apple, cotoneaster, hawthorn, etc.) whose fruits consist of five capsules (called "cores") in a fleshy or stony endocarp, surrounded by fleshy mesocarp and hypanthium tissue. This fruit is called a pome. While this group remains an identified clade, to separate it at the subfamily level would leave the remaining genera as a paraphyletic group, so it has been expanded to include the former Spiraeoideae and Prunoideae. The subfamily has sometimes been referred to by the name "Spiraeoideae", but this is not permitted by the International Code of Nomenclature for algae, fungi, and plants.
• Subfamily Dryadoideae: Fruits are achenes with hairy styles. Includes five genera (Dryas, Cercocarpus, Chamaebatia, Cowania and Purshia), most species of which form root nodules which host the nitrogen-fixing bacterium Frankia.