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.

GEUM

Barbara Ertter

Perennial; glands inconspicuous
Stem ascending to erect
Leaves generally basal, odd-1-pinnate; leaflets lobed, unevenly toothed, often alternately large and small
Inflorescence: generally cyme, open
Flower: hypanthium shallow; bractlets generally 5; sepals 5; petals 5; stamens > 20; pistils many, ovaries superior, continuous to style at top
Fruit: achene ± flat; style long, persistent
Species in genus: 40–50 species: generally n temp, arctic
Etymology: (Latin: ancient name)

Native

G. macrophyllum Willd.

BIGLEAF AVENS

Plant tufted, drying greenish
Stem generally 20–100 cm
Leaf generally 10–45 cm; main leaflets generally 2–4 per side, generally << terminal leaflet; terminal leaflet generally 8–10 cm, ± bluntly cordate-reniform, 3-lobed < 3/4 to base, irregularly toothed
Inflorescence generally 3–10-flowered; pedicels straight
Flower rotate; bractlets generally ± 2 mm, linear, often some missing; sepals reflexed, 3–5 mm; petals 3–7 mm, obovate-round, shallowly notched, yellow, deciduous
Fruit: achene body 2.5–3.5 mm; style 2.5–5 mm, hooked below generally deciduous tip, glabrous to glandular
Chromosomes: n=21
Ecology: Meadows, streambanks
Elevation: < 3300 m.
Bioregional distribution: Northwestern California, High Cascade Range, High Sierra Nevada, San Bernardino Mountains, Great Basin Floristic Province
Distribution outside California: to n&e N.America
Flowering time: May–Aug
Varieties indistinct in CA. Some plants from s SNH approach G. aleppicum
Horticultural information: 4, 5, 6 &IRR: 1, 2, 7, 15, 16, 17 &SHD: 3, 14, 18, 19, 20, 21, 22, 23, 24; rather INV.