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Athysanus pusillus

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 pusillus (Hook.) Greene
Habit: Hairy at least proximally. Stem: (2)5--30(50) cm. Leaf: basal 4--25 mm, 1--8 mm wide, oblanceolate to obovate or oblong, entire or dentate; cauline 1--6, like basal, sessile. Flower: sepals 0.5--1 mm; petals 1--3 mm, spoon-shaped, occasionally 0. Fruit: 2--2.5 mm wide, +- round, smaller hairs branched; style to 0.2 mm; pedicel (1.5)2--4(6) mm. Seed: to 1.2 mm. Chromosomes: 2n=26.
Ecology: Grassy, open slopes, rocky outcrops, chaparral, flats, floodplains, cliffs, ledges; Elevation: < 2000 m. Bioregional Distribution: CA-FP, MP, DMtns (Granite Mtns); Distribution Outside California: to British Columbia, Montana, Nevada, Mexico. Flowering Time: Feb--Jun
Unabridged Synonyms: Thysanocarpus pusillus Hook.
Jepson eFlora Author: Ihsan A. Al-Shehbaz
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botanical illustration including Athysanus pusillus


Citation for this treatment: Ihsan A. Al-Shehbaz 2012, Athysanus pusillus, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on November 17, 2018.

Citation for the whole project: Jepson Flora Project (eds.) 2018, Jepson eFlora,, accessed on November 17, 2018.

Athysanus pusillus
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© 2008 Keir Morse
Athysanus pusillus
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© 2008 Steve Matson
Athysanus pusillus
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© 2009 Barry Breckling
Athysanus pusillus
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© 2004 Julie Kierstead Nelson
Athysanus pusillus
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© 2004 Julie Kierstead Nelson
Athysanus pusillus
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© 2008 Steve Matson

More photos of Athysanus pusillus in CalPhotos

Geographic subdivisions for Athysanus pusillus:
CA-FP, MP, DMtns (Granite Mtns);
Markers link to CCH specimen records. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues. Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
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.
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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.