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.

HORKELIA

Barbara Ertter

Perennial, generally ± glandular, generally resinous-smelling; caudex generally branched
Stem generally ascending to erect
Leaves generally basal, odd-1-pinnate, generally ± flat; cauline alternate, reduced upward; uppermost lateral leaflets generally ± fused with terminal
Inflorescence: cyme, open or of dense clusters; pedicels generally straight
Flower: hypanthium a ± flat-bottomed cup, width ± 2 X length; bractlets 5, generally 2/3 sepals; sepals 5, often reflexed; petals 5, generally ± = sepals, blunt, white; stamens 10, filaments flat, often forming a tube; pistils 2–many, ovaries superior, styles jointed below fruit tip, ± thicker at base
Fruit: achene
Species in genus: 19 species: w North America
Etymology: (J. Horkel, German plant physiologist, 1769–1846)
Data apply to basal leaves, pressed hypanthia.

Native

H. clevelandii (Greene) Rydb.

Plant tufted, green to grayish
Stem 10–50 cm; hairs spreading
Leaf 5–18 cm; leaflets 6–12 per side, generally ± separated, generally 5–12 mm, wedge-shaped to ± round, 5–10-toothed ± 1/3 to base, ± densely hairy
Inflorescence generally open, ± 5–30-flowered; pedicels generally 1.5–6 mm
Flower: hypanthium width 2–4 mm, ± 2 X length, inner wall glabrous; bractlets 0.5–1.5 mm wide, generally lanceolate; sepals ± 3–4 mm; petals 3–6 mm, widely oblanceolate; filaments 0.5–1.5 mm, bases ± 0.5 mm wide, anthers 0.5–1 mm; pistils generally 10–50, styles ± 1.5 mm
Fruit ± 1.2 mm
Ecology: Meadows, under pines, on granite
Elevation: 1200–2500 m.
Bioregional distribution: Peninsular Ranges
Distribution outside California: n Baja California (where some possibly distinct)
Synonyms: H. bolanderi subsp. c. (Greene) D.D. Keck
Horticultural information: IRR: 1, 2, 3, 7, 15, 16, 17 &SHD: 14, 18, 19, 20, 21, 22, 23, 24; GRCVR.