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Vascular Plants of California
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Athysanus unilateralis

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: AthysanusView DescriptionDichotomous Key

Habit: Annual; hairs simple, or short-stalked with 2--4-rays. Stem: simple or branched at base, leafy. Leaf: basal not rosetted, short petioled, entire or dentate; cauline short-petioled or sessile, base not lobed, entire or dentate. Inflorescence: 1-sided; bracts 0. Flower: sepals erect, early-deciduous, base not sac-like; petals < to > sepals or rudimentary, white. Fruit: silicle, reflexed, indehiscent or late-dehiscent, unsegmented, round or obovate to elliptic, flat parallel to septum, glabrous to hairy; pedicel recurved. Seed: 1 or 6--12, in 1 row, flat, not winged.
Species In Genus: 2 species: western North America, northwestern Mexico. Etymology: (Greek: without fruit fringe)
Unabridged Note: Jepson 1901 Flower W Calif:224 united Athysanus and Heterodraba under the former, thus establishing nomenclatural priority. The 2 genera are indistinguishable in every character except those in the key below. Molecular data support the placement of the combined genus near Draba and Arabis.
eFlora Treatment Author: Ihsan A. Al-Shehbaz
Athysanus unilateralis (M.E. Jones) Jeps.
Stem: hairy; branched near base, prostrate to ascending, (3)7--25(35) cm. Leaf: basal nearly sessile, 0.5--2.2 cm, oblanceolate to obovate or oblong, entire to each side 1-toothed; hairs 3--4-rayed; cauline 2--5, tapered at base. Flower: sepals 0.6--1 mm; petals 1.3--1.7 mm. Fruit: 3--5 mm, obovate to elliptic or round; style 0.1--0.2 mm; pedicel 1--2(3) mm. Seed: 0.9--1.2 mm, plump, oblong.
Ecology: Uncommon. Grassy, open slopes, flats, clay soils, floodplains, gypsum-clay slopes; Elevation: 100--900 m. Bioregional Distribution: CaRF, s SNF, Teh, GV, SCoR; Distribution Outside California: Oregon, Baja California. Flowering Time: Feb--May
Synonyms: Draba unilateralis M.E. Jones; Heterodraba unilateralis (M.E. Jones) Greene
Jepson eFlora Author: Ihsan A. Al-Shehbaz
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)

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Botanical illustration including Athysanus unilateralis

botanical illustration including Athysanus unilateralis


Citation for this treatment: Ihsan A. Al-Shehbaz 2012, Athysanus unilateralis, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on February 28, 2021.

Citation for the whole project: Jepson Flora Project (eds.) 2021, Jepson eFlora,, accessed on February 28, 2021.

Athysanus unilateralis
click for enlargement
© 2016 Neal Kramer
Athysanus unilateralis
click for enlargement
© 2016 Neal Kramer
Athysanus unilateralis
click for enlargement
© 2016 Neal Kramer
Athysanus unilateralis
click for enlargement
© 2016 Neal Kramer
Athysanus unilateralis
click for enlargement
© 2008 Aaron Schusteff
Athysanus unilateralis
click for enlargement
© 2016 Neal Kramer

More photos of Athysanus unilateralis in CalPhotos

Geographic subdivisions for Athysanus unilateralis:
CaRF, s SNF, Teh, GV, SCoR
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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).