Jepson Flora Project: Jepson Interchange    

 
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Jepson Interchange (more information)
©Copyright 1993 by the Regents of the University of California

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  • Up-to-date information about California vascular plants is available from the Jepson eFlora.

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.

PETROPHYTON

ROCK SPIRAEA

Thomas J. Rosatti

Shrub, matted, scapose
Leaves crowded, evergreen, generally ± oblanceolate, entire
Inflorescence ± spike-like
Flower: bractlets on hypanthium 0; sepals persistent; petals white; stamens 20–40; pistils generally 5, simple, ovary superior, hairy, styles thread-like
Fruit: follicles, dehiscing along both sutures
Seeds 1–several, linear
Species in genus: ± 4 species: w North America
Etymology: (Greek: rock plant)

Native

P. caespitosum (Nutt.) Rydb.

Plant 3–8 dm wide; rosettes many
Stems very stout
Leaf 1–3-veined below
Inflorescence 4–14 cm; peduncle 3–10 cm, bracted
Flower: sepals ± 1.5 mm, narrowly ovate, acute; petals ± 1.5 mm, generally obtuse; style ± 3 mm
Fruit ± 2 mm
Seeds 1–2, ± 1.5 mm, linear to obovoid, brown, smooth
Ecology: Limestone soils, pinyon/juniper woodland, coniferous forest
Elevation: 1200–3000 m.
Bioregional distribution: s High Sierra Nevada, White and Inyo Mountains, Desert Mountains
Distribution outside California: to Rocky Mtns

Native

subsp. acuminatum (Rydb.) Munz


Leaf 10–18 mm, sparsely hairy
Ecology: Limestone cliffs, coniferous forest
Elevation: 1200–2300 m.
Bioregional distribution: s High Sierra Nevada
Horticultural information: TRY; DFCLT.

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