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.

BRASSICACEAE

MUSTARD FAMILY

Reed C. Rollins, except as specified

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 1–many 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 80:686–699; 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. lyallii S. Watson

Perennial; caudex branched; hairs multibranched, ± minute
Stems few–many, < 15 cm, glabrous
Leaves: basal narrowly petioled, 1–3 cm, entire; cauline few, well spaced, sessile, 1–2 cm, lanceolate to oblong, base generally tapered, tip acute
Flower: petals spoon-shaped, rose to purplish
Fruit erect to ± spreading, 3–5 cm, straight, glabrous; tip tapered; style short or 0
Seed round, winged
Ecology: Rock crevices, slopes, ridges
Elevation: 2400–3800 m.
Bioregional distribution: High Cascade Range, High Sierra Nevada, Warner Mountains, White and Inyo Mountains
Distribution outside California: to British Columbia, Wyoming
2 vars. total.

Native

var. nubigena (J.F. Macbr. & Payson) Rollins


Stem ± prostrate to ascending, slender
Leaves: basal 1–2.4 mm wide, linear to linear-oblanceolate, tip acute to acuminate
Ecology: Rock slides, open ridges
Elevation: 2900–3800 m.
Bioregional distribution: High Sierra Nevada, White and Inyo Mountains
Distribution outside California: to Idaho, Wyoming
Flowering time: Jul–Aug

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