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. truncata Rydb.

RAMONA HORKELIA

Plant tufted, green
Stem 20–60 cm
Leaf 4–13 cm; leaflets 1–3 per side, separated, 10–30 mm, oblong to obovate, generally > 20-toothed < 1/4 to midvein, ± glabrous; terminal leaflet largest, generally unlobed
Inflorescence open, 5–20-flowered; pedicels generally 4–20 mm
Flower: hypanthium width 5–8 mm, > 2 X length; bractlets ± 2–3 mm wide, widely ovate; sepals generally 3.5–5.5 mm; petals 5–7 mm, ± 5 mm wide, ± round; filaments 1–2 mm, bases 0.5–2 mm wide, anthers ± 1 mm; pistils 50–80, styles ± 2 mm
Fruit ± 1.3 mm
Ecology: Dry red clay, open chaparral
Elevation: 400–1300 m.
Bioregional distribution: Peninsular Ranges
Distribution outside California: n Baja California
Horticultural information: In cultivation.