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.

HORKELIELLA

Barbara Ertter

Perennial, tufted, ± glandular; odor ± resinous
Stem ascending to erect, 15–50 cm
Leaves generally basal, odd-pinnately compound; leaflets many, ± overlapped, toothed to palmately divided, segments ± oblanceolate
Inflorescence: ± cyme; pedicels straight
Flower: hypanthium cup-like, flat-bottomed; bractlets 5; sepals 5, often reflexed; petals 5, white or pinkish, midvein often reddish; stamens 20, filaments ± flat, often an erect tube; pistils many, ovaries superior, style jointed below fruit tip, ± rough, thick
Fruit: achene, ± 1.5 mm
Species in genus: 2 species: CA
Etymology: (Latin: small Horkelia )
Fl ± like that of Horkelia.

Native

H. congdonis (Rydb.) Rydb.

Plant green, generally glandular-sticky
Leaves: basal generally 8–25 cm, leaflets 25–35 per side, generally 2–6 mm, 5–10-lobed; cauline 2–7
Inflorescence ± dense; pedicels generally ± 2 mm
Flower ± 15 mm wide; sepals 4–8 mm; petals 3–6 mm, oblong-oblanceolate; anther ± 1 mm, filaments 1.5–3 mm, central longest; style 2–5 mm
Ecology: Meadows in sagebrush flats
Elevation: 1500–2900 m.
Bioregional distribution: c High Sierra Nevada (e slope), w East of Sierra Nevada
Flowering time: Jul–Aug
Synonyms: Ivesia purpurascens (S. Watson) D.D. Keck subsp. c. (Rydb.) D.D. Keck
Horticultural information: DRN, IRR, SUN: 1, 2, 3, 7, 15, 16, 17.