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Caulanthus cooperi

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: CaulanthusView DescriptionDichotomous Key

Habit: Annual to perennial herb, glabrous or hairs simple (forked). Leaf: basal rosetted or not, petioled, entire, dentate or pinnately lobed, generally deciduous; cauline petioled, or sessile with bases lobed or sagittate. Inflorescence: elongated. Flower: calyx urn-shaped or cylindric, sepals erect (spreading), base sac-like or not; petals yellow, purple, brown, or white, generally channeled, margin wavy or not; stamens in 3 pairs of equal length, or 4 long and 2 short, (all equal), free or filaments of longer pair(s) fused. Fruit: silique, linear, dehiscent, unsegmented, +- sessile, cylindric (flat perpendicular or parallel to septum); stigma entire or 2-lobed. Seed: 24--210, 1 row per chamber, oblong to ovate (+- spheric), plump, wing 0.
Species In Genus: 17 species: southwestern United States, northwestern Mexico. Etymology: (Greek: stem flower, in reference to insertion of flowers along stem)
eFlora Treatment Author: Ihsan A. Al-Shehbaz

Caulanthus cooperi (S. Watson) Payson
Habit: Annual. Stem: 1--8 dm, generally weak, not inflated, generally wavy and branched distally, glabrous or hairs appressed, 2-rayed, minute. Leaf: basal 1--8 cm, coarsely dentate to lobed (entire), oblanceolate to spoon-shaped; cauline sessile, lanceolate to oblong, entire to dentate, base lobed to clasping. Inflorescence: terminal sterile flower cluster 0. Flower: sepals 3--6.5 mm, +- purple or yellow-green; petals 4.5--9 mm, not wavy, +- purple or yellow-green; stamens 4 long, 2 short, filaments free. Fruit: spreading to reflexed, 2--6 cm, 1.5--2.5 mm wide, cylindric, generally curved; style 0.2--2.7 mm, stigma +- 2-lobed; pedicel reflexed, 1--4.5 mm. Seed: 24--48, 1--2 mm, oblong; cotyledons entire. Chromosomes: 2n=28.
Ecology: Common. Open, sandy, gravelly soil, generally among shrubs; Elevation: 300--2500 m. Bioregional Distribution: n TR, e PR, s SNE, D; Distribution Outside California: to southwestern Utah, western Arizona, Baja California. Flowering Time: Mar--Apr Note: Plants with stem, fruit +- green or straw-colored generally mixed with plants with stem, fruit dark purple.
eFlora Treatment Author: Ihsan A. Al-Shehbaz
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Citation for this treatment: Ihsan A. Al-Shehbaz 2017. Caulanthus cooperi, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on August 22, 2017.

Citation for the whole project: Jepson Flora Project (eds.) 2017. Jepson eFlora,, accessed on August 22, 2017.

Caulanthus cooperi
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© 2009 Aaron Schusteff
Caulanthus cooperi
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© 2012 Keir Morse
Caulanthus cooperi
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© 2012 Keir Morse
Caulanthus cooperi
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© 2012 Steve Matson
Caulanthus cooperi
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© 2012 Keir Morse
Caulanthus cooperi
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© 2014 Steve Matson

More photos of Caulanthus cooperi in CalPhotos

Geographic subdivisions for Caulanthus cooperi:
n TR, e PR, s SNE, D;
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.
Blue line denotes eFlora flowering time.