1 Leaves palmately-pedately 5-foliolate (the lateral 2 leaflets on each side borne on a common Y-shaped stalk).

  2 Leaflets entire; sap milky

  2 Leaflets toothed; sap clear

1 Leaves palmately compound (all the leaflets attached at a single point).

    3 Leaves > 6 dm wide

    3 Leaves < 3 dm wide.

      4 Leaflets with entire margins; [non-natives].

        5 Plants deciduous woody climbers (but not twining, or specialized climbing structures); leaflets usually 5 per leaf (occasionally 3 or 7); flowers maroon-colored, lacking petals but with 3 prominent sepals, the inflorescences axillary

        5 Plants evergreen shrubs or trees (occasionally partially epiphytic); leaflets usually 7-9 per leaf (occasionally 5 or 10); flowers yellowish-green or red, petals present, lacking showy prominent sepals, the inflorescences (most often) terminal

      4 Leaflets with serrate margins; [natives and non-natives].

          6 Stems unarmed or with paired nodal spines.

             7 Inflorescence an umbel; leaves evergreen, glossy; stems often with paired nodal spines

             7 Inflorescence a panicle; leaves deciduous, dull; stems unarmed

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]