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.

HOLODISCUS

Richard A. Lis

Shrub, ± hairy
Stem 3–60 dm; bark reddish, in age gray, shredding
Leaves simple, alternate, 0.3–12 cm, thin to leathery, toothed; base truncate to generally ± wedge-shaped; lower surface strongly veined; stipules 0; petiole distinct or not
Inflorescence: panicle, ± terminal, dense, 2.5–25 cm, ± conic, many-flowered, persistent; pedicel slender, bractlets 1–3
Flower: hypanthium 3–5 mm wide, saucer-shaped, prominent nectary-disk below inner rim; sepals 5, 1–2 mm; petals 5, 1.5–2 mm, ± ovate, generally white; stamens 15–20, wider at base; pistils 5, ovaries superior, 2-ovuled, hairs dense, bristle-like, persistent in fruit, style 1 mm, persistent, stigma ± 2-lobed
Fruit: achenes 5, 1–1.5 mm, often with sessile glands
Species in genus: 5 species: w North America, C.Am, n South America
Etymology: (Greek: whole disk)
Spp. highly variable; leaves of peg-like stems best for identification; complexity in c SNH evidently from local climatic variation, hybridization.