ROSACEAE

ROSE FAMILY

Annual to tree
Leaves simple to pinnately to palmately compound, generally alternate; stipules free to fused, persistent to deciduous
Inflorescence: cyme, raceme, panicle, or flowers solitary
Flower generally bisexual, radial; hypanthium free or fused to ovary, saucer- to funnel-shaped, often with bractlets alternate with sepals; sepals generally 5; petals generally 5, free; stamens (0)5–many, pistils (0)1–many, simple or compound; ovary superior to inferior, styles 1–5
Fruit: achene, follicle, drupe, pome, or blackberry- to raspberry-like
Seeds generally 1–5
Genera in family: 110 genera, ± 3000 species: worldwide, especially temp. Many cultivated for ornamental and fruit, especially Cotoneaster , Fragaria , Malus , Prunus , Pyracantha, Rosa , and Rubus
Reference: [Robertson 1974 J Arnold Arbor 55:303–332,344–401,611–662]
Family description, key to genera by Barbara Ertter and Dieter H. Wilken.

POTENTILLA

CINQUEFOIL

Barbara Ertter

Annual to shrub; odor resinous or 0
Leaves generally basal, odd-1-pinnate to 1-palmate or 1-ternate; leaflets ± toothed or lobed, terminal generally ± = lateral
Inflorescence: cyme, generally ± open; pedicels generally ± straight
Flower: hypanthium ± shallow; bractlets 5; sepals generally 5, ± triangular; petals generally 5, generally = or > sepals, generally ± widely obcordate, generally yellow; stamens generally 20; pistils generally many, styles generally jointed near tip
Fruit: achene
Species in genus: 200–500 species: n temp
Etymology: (Latin: diminutive of powerful, for reputed medicinal value)
Reference: [Clausen, Keck, & Hiesey 1940 Carn Inst Wash Pub 520:26–195]
P. anglica Laicharding is a waif from cultivated: stem trailing; pedicels 2–8 cm, slender; sepals and petals generally 4; leaflets 3–5.

Native

P. gracilis Hook.

Plant tufted from short, thick rhizome; glands generally 0 or hidden
Stem ± ascending, generally 20–100 cm, strigose to spreading-hairy
Leaves palmate; basal generally 6–30 cm, leaflets generally 5–7, central leaflet ± oblanceolate, toothed or lobed ± throughout, hairy especially below
Inflorescence few–many-flowered
Flower: hypanthium generally 3–5 mm wide; petals generally 4–10 mm; filaments 1.5–2.5 mm, anthers 0.6–1.6 mm; styles 1.5–2 mm, slender
Fruit 1–1.5 mm, smooth, light brown
Chromosomes: 2n=52–109
Ecology: Common. Meadows, open forests
Elevation: 120–3500 m.
Bioregional distribution: Northwestern California (except sw), Cascade Range, High Sierra Nevada, Tehachapi Mountain Area, Transverse Ranges, Peninsular Ranges, Great Basin Floristic Province
Distribution outside California: w N.America
Variation complex; many but not all plants are assignable to the following extremes.

Native

var. flabelliformis (Lehm.) Torr. & A. Gray

Hairs generally appressed
Stem generally 50–100 cm
Leaves: basal central leaflet 50–90 mm, tomentose below, sparsely hairy above, lobed > 3/4 to midvein, lobes generally widest at base, often few-toothed
Flower: petals 7–10 mm
Chromosomes: 2n=± 56–65
Ecology: Moist or wet meadows
Elevation: 1050–1600 m.
Bioregional distribution: Modoc Plateau
Distribution outside California: to sw Canada
Similar plants sporadic elsewhere (e.g., c SNH, Yosemite Valley)
Synonyms: P. f. Lehm
Horticultural information: TRY.