1 Leaflets < 5 mm wide, entire; densely-branched shrub to 1 m tall; flowers yellow; [tribe Potentilleae]

1 Leaflets > 10 mm wide, serrate or crenate; shrubs, trees, or woody vines (see below); flowers white, pink, or purplish (rarely yellow in Rosa).

..2 Leaves 1-pinnately compound, generally with > 11 leaflets; inflorescence a terminal panicle or corymb with numerous (> 100) flowers, the petals white and < 4 mm long; fruit a pome or follicle; upright tree or shrub with unarmed stems.

....3 Inflorescence a panicle; fruit a follicle; shrub, to 2 m tall; [tribe Sorbarieae]

....3 Inflorescence a corymb; fruit a pome; tree, generally > 2 m tall; [tribe Pyreae]

..2 Leaves palmately or 1-pinnately compound, generally with < 11 leaflets; inflorescences axillary or terminal panicles or corymbs with few (<15) flowers, the petals white, pink, or purplish (rarely yellow) and > 6 mm long; fruit a hip or aggregate of drupelets; arching or upright shrubs or climbing or sprawling woody vines, the stems usually armed with prickles.

......4 Fruit a hip, developing from a globose to urceolate hypanthium, enclosing the ovaries and achenes, except for the apical orifice; leaflets usually acute to obtuse at the apex; leaflet margins crenulate or serrulate; [tribe Roseae]

......4 Fruit an aggregate of drupelets, developing from a flattish or hemispheric hypanthium, with the ovaries and drupelets exposed; leaflets usually acuminate at the apex; leaflet margins serrate or doubly serrate; [tribe Rubeae]