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Vascular Plants of California
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Arabis pycnocarpa var. pycnocarpa

Higher Taxonomy
Family: Brassicaceae (Cruciferae)View DescriptionDichotomous Key
Habit: Annual to shrub; sap pungent, watery. Leaf: generally simple, alternate; generally both basal, cauline; stipules 0. Inflorescence: generally raceme, generally not bracted. Flower: bisexual, generally radial; sepals 4, generally free; petals (0)4, forming a cross, generally white or yellow to purple; stamens generally 6 (2 or 4), 4 long, 2 short (3 pairs of unequal length); ovary 1, superior, generally 2-chambered with septum connecting 2 parietal placentas; style 1, stigma entire or 2-lobed. Fruit: capsule, generally 2-valved, "silique" (length >= 3 × width) or "silicle" (length < 3 × width), dehiscent by 2 valves or indehiscent, cylindric or flat parallel or perpendicular to septum, segmented or not. Seed: 1--many, in 1 or 2 rows per chamber, winged or wingless; embryo strongly curved.
Genera In Family: +- 330 genera, 3780 species: worldwide, especially temperate. Note: Highest diversity in Mediterranean area, mountains of southwestern Asia, adjacent central Asia, western North America; some Brassica species are oil or vegetable crops; Arabidopsis thaliana used in experimental molecular biology; many species are ornamentals, weeds. Aurinia saxatilis (L.) Desvaux in cultivation only. Aubrieta occasional waif in central NCoR, Carrichtera annua (L.) DC. in SCo, Iberis sempervirens L., Iberis umbellata L. in PR, Teesdalia coronopifolia (Bergeret) Thell., Teesdalia nudicaulis (L.) W.T. Aiton in southern NCoRO, CCo. Cardaria, Coronopus moved to Lepidium; Caulostramina to Hesperidanthus; Guillenia to Caulanthus; Heterodraba to Athysanus; California taxa of Lesquerella to Physaria; Malcolmia africana to Strigosella.
eFlora Treatment Author: Ihsan A. Al-Shehbaz, except as noted
Scientific Editor: Douglas H. Goldman, Bruce G. Baldwin.
Genus: ArabisView DescriptionDichotomous Key

Common Name: ROCKCRESS
Habit: Annual, biennial, perennial herb; base not woody; hairs simple, forked, or stellate; caudex branched or not. Stem: branched or not, leafy. Leaf: basal rosetted, petioled, entire or dentate; cauline sessile, entire or dentate, base lobed or not. Flower: sepals erect or ascending, base of lateral pair sac-like or not; petals spoon-shaped to oblong, oblanceolate, or obovate, white to pink or deep purple. Fruit: silique, erect to spreading, linear, dehiscent, unsegmented, straight, flat parallel to septum, glabrous. Seed: 12--110, 1 row per chamber, flat, winged or margined.
Species In Genus: < 70 species: temperate North America, Eurasia, northern Africa. Etymology: (Latin: of Arabia) Note: Most species of Arabis in TJM (1993) moved to Boechera; Arabis glabra to Turritis. California record of Arabis aculeolata Greene not confirmed.
eFlora Treatment Author: Ihsan A. Al-Shehbaz
Arabis pycnocarpa M. Hopkins var. pycnocarpa
Habit: Biennial or weak perennial herb; caudex branched or not; hairs simple and short-stalked forked, coarse, spreading. Stem: 1--several, simple or branched distally, erect, 1--8 dm. Leaf: basal short-petioled, 2--10 cm, oblong to obovate or spoon-shaped, entire to dentate; cauline (7)10--45(61), ovate to oblong or lanceolate, sagittate or lobed at base. Flower: sepals 2--4 mm; petals 3.5--5(5.5) mm, 1--2(2.5) mm wide, white. Fruit: (3.5)4--6 cm, 0.8--1(1.2) mm wide; style (0.2)0.5--1 mm; pedicel 0.5--1.5 cm, glabrous to sparsely hairy. Seed: (54)60--86, oblong or +- round; wing to 0.2 mm, continuous. Chromosomes: 2n=32.
Ecology: Gravelly soils, swales, disturbed sites, meadows, shady slopes, occasionally moist; Elevation: < 2500 m. Bioregional Distribution: KR, NCoRO, CaR, SN, SnBr, W&I; Distribution Outside California: Canada, United States except Alaska, Hawaii. Flowering Time: Mar--Jul Note: Other variety in Ontario, central United States.
Synonyms: Arabis hirsuta (L.) Scop. var. pycnocarpa (M. Hopkins) Rollins
Unabridged Synonyms: Arabis hirsuta subsp. pycnocarpa (M. Hopkins) Hultén
Jepson eFlora Author: Ihsan A. Al-Shehbaz
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)

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Citation for this treatment: Ihsan A. Al-Shehbaz 2012, Arabis pycnocarpa var. pycnocarpa, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on June 17, 2021.

Citation for the whole project: Jepson Flora Project (eds.) 2021, Jepson eFlora,, accessed on June 17, 2021.

Arabis pycnocarpa var. pycnocarpa
click for enlargement
© 2016 Keir Morse
Arabis pycnocarpa var. pycnocarpa
click for enlargement
© 2016 Keir Morse
Arabis pycnocarpa var. pycnocarpa
click for enlargement
© 2015 Barry Breckling
Arabis pycnocarpa var. pycnocarpa
click for enlargement
© 2015 Barry Breckling
Arabis pycnocarpa var. pycnocarpa
click for enlargement
© 2016 Keir Morse
Arabis pycnocarpa var. pycnocarpa
click for enlargement
© 2016 Keir Morse

More photos of Arabis pycnocarpa var. pycnocarpa in CalPhotos

Geographic subdivisions for Arabis pycnocarpa var. pycnocarpa:
KR, NCoRO, CaR, SN, SnBr, W&I
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map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).


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Data provided by the participants of the  Consortium of California Herbaria.
View all CCH records
All markers link to CCH specimen records. The original determination is shown in the popup window.
Blue markers indicate specimens that map to one of the expected Jepson geographic subdivisions (see left map). Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.

CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa, if there are more than 1 infraspecific taxon in CA.
Blue line denotes eFlora flowering time (fruiting time in some monocot genera).