Jepson Flora Project: Jepson Interchange    

 
link to manual TREATMENT FROM THE JEPSON MANUAL (1993) previous taxon | next taxon
Jepson Interchange (more information)
©Copyright 1993 by the Regents of the University of California

    THIS PAGE IS NO LONGER UPDATED
    AND IS MAINTAINED FOR ARCHIVAL PURPOSES ONLY
  • 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. holboellii Hornem.

Biennial, perennial herb; caudex branched or not; hairs generally multibranched
Stems 1–several, erect
Leaves: basal 1–5 cm, linear-oblanceolate to widely spoon-shaped, tip acute, hairs dense; cauline sessile, 2–4 cm, oblong to lanceolate, entire, lower surface densely hairy, upper surface ± hairy to not
Flower: petals purplish pink to whitish
Fruit 3–7 cm, generally ± straight, glabrous; pedicel arched or recurved to ± reflexed, (4)6–16 mm, straight to ± curved, slender, hairy or not
Seed round; wing narrow all around
Ecology: Rocky slopes, open sites
Elevation: 500–3500 m.
Bioregional distribution: Northwestern California, Cascade Range, Sierra Nevada, San Francisco Bay Area, Great Basin Floristic Province
Distribution outside California: to Alaska, e Canada, NE
5 vars. in North America, difficult to distinguish, especially in flower.

Native

var. retrofracta (Graham) Rydb.


Stem branched above, 2–9 dm; hairs throughout or ± 0 above
Leaves minutely hairy; basal > 3 mm wide, entire to ± dentate; cauline base lobed, often ± clasping stem
Fruit generally straight; pedicel reflexed, generally straight
Chromosomes: 2n=14, 21+1
Ecology: Common. Rocky slopes, open areas
Elevation: 500–2400 m.
Bioregional distribution: Northwestern California, Cascade Range, Sierra Nevada, San Francisco Bay Area, Great Basin Floristic Province
Distribution outside California: to Alaska, e Canada
Flowering time: May–Jul

previous taxon | next taxon
bioregional map for ARABIS%20holboellii%20var.%20retrofracta being generated
 


Retrieve Jepson Interchange Index to Plant Names entry for Arabis holboellii var. retrofracta
Retrieve dichotomous key for Arabis
Overlay Consortium of California Herbaria specimen data by county on this map
Show other taxa with the same California distribution | Read about bioregions | Get lists of plants in a bioregion
Return to the Jepson Interchange main page
Return to treatment index page
Glossary


University & Jepson Herbaria Home Page |
General Information | University Herbarium | Jepson Herbarium |
Visiting the Herbaria | On-line Resources | Research |
Education | Related Sites
Copyright © by the Regents of the University of California