TREATMENT FROM THE JEPSON MANUAL (1993) |
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©Copyright 1993 by the Regents of the University of California
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Annual to subshrub
Leaves generally basal and cauline, alternate, generally simple; stipules 0
Inflorescence: generally raceme
Flower bisexual; sepals 4, free; petals (0)4, free, generally white or yellow, often clawed; stamens generally (2,4)6, generally 4 long, 2 short; ovary 1, superior, chambers generally 2, septum membranous, connecting 2 parietal placentas, style 1, stigma simple or 2-lobed
Fruit: generally capsule ("silique") with 2 deciduous valves, sometimes breaking transversely or indehiscent
Seeds 1many per chamber
Genera in family: 300+ genera, 3000+ species: worldwide, especially cool regions; some cultivated for food (especially Brassica, Raphanus ) and ornamental
Recent taxonomic note: Recently treated to include Capparaceae [Rodman et al. 1993 Ann Missouri Bot Gard 80:686699; Rollins 1993 Cruciferae of Continental North America. Stanford Univ Press]
Family description, key to genera by Robert A. Price.ARABIS
ROCK CRESS
Biennial, perennial herb; base woody or not; hairs 0 to dense, simple, forked, stellate, or multibranched; caudex branched or not
Stem branched or not, cylindric, leafy
Leaves: basal petioled, entire or dentate; cauline generally sessile, entire or dentate, base often lobed, often clasping stem
Inflorescence: bracts 0
Flower erect to reflexed; sepals erect; petals spoon-shaped to oblong and narrowed at base or narrowly obovate, white to deep purple, rarely straw-colored
Fruit erect to reflexed, linear, straight to curved, flat parallel to septum, rarely ± cylindric
Seeds ± many, generally 1 row per chamber, flat or plump, winged or not; embryonic root at edges of both cotyledons
Species in genus: ± 120 species: temp North America, Eurasia, Africa
Etymology: (Latin: of Arabia)
Native A. davidsonii Greene
Perennial; caudex thick, simple or branched, old leaf bases present
Stems several, simple, 515 cm, slender, glabrous
Leaves: basal 38 cm, long-petioled, oblanceolate, entire or rarely few-toothed near tip, glabrous, thickish, tip obtuse; cauline few, sessile, 615 mm, oblong, base tapered
Flower: petals spoon-shaped, white to pale purple
Fruit ascending, 35 cm, ± straight to ± curved; pedicel ascending, 11.5 cm; style very short
Seed round; wing narrow
Ecology: Uncommon. Rock crevices, large granite outcrops
Elevation: 15003500 m.
Bioregional distribution: Sierra Nevada
Distribution outside California: e Oregon, n Nevada
Horticultural information: DRN, SHD: 6, 17 &IRR: 1, 2, 3, 7, 14, 15, 16.
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