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.

SORBUS

MOUNTAIN ASH

Thomas J. Rosatti

Shrub or tree
Leaves odd-1-pinnate in CA, petioled, deciduous; leaflets generally toothed, terminal sometimes partly fused to uppermost lateral(s)
Inflorescence: panicle, many-flowered
Flower: sepals 5; petals 5; stamens 15–20; ovary generally inferior, styles generally free
Fruit: pome; chambers 1–5, 1–2-seeded
Species in genus: ± 80 species: n temp
Etymology: (Latin: ancient name)
Reference: [Jones 1939 J Arnold Arbor 20:1–43]
Intergrading: native species might all = S. sitchensis.

Introduced

S. aucuparia L.

Tree < 15 m; stem-bud hairs dense, evenly distributed, whitish
Leaf: leaflets 9–17, 3–5 cm, oblong-lanceolate
Inflorescence: pedicel hairs generally dense
Flower: petals ± 4 mm, ± round
Fruit 9–11 mm, bright red
Seeds ± 4 mm, ovate, ± flat, light brown
Chromosomes: 2n=34
Ecology: Disturbed places, generally near dwellings
Elevation: generally < 1700 m.
Bioregional distribution: San Francisco Bay Area, San Bernardino Mountains (expected elsewhere)
Distribution outside California: native to Europe