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Lepidium didymum

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: LepidiumView DescriptionDichotomous Key

Habit: Annual to perennial herb (shrub); hairs 0 or simple. Leaf: basal rosetted or not, petioled, entire, dentate, to 1--3-pinnately lobed; cauline short-petioled to sessile, base occasionally lobed to clasping. Inflorescence: elongated or congested. Flower: sepals erect or spreading, oblong to ovate, base not sac-like; petals linear to obovate, white or yellow (pink or purple), occasionally reduced or 0; stamens 2, 4, or 6. Fruit: silicle, generally dehiscent, oblong to ovate, obcordate, or round (spectacle-shaped), flat perpendicular to septum (inflated), unsegmented. Seed: 2(4), gelatinous when wet; wing narrow or 0.
Species In Genus: 220 species: all continents except Antarctica. Etymology: (Greek: little scale, from fruit)

Lepidium didymum L.
Habit: Annual, fetid, glabrous or hairy. Stem: erect to decumbent, few to many from base, 1--4.5(7) dm, branched distally. Leaf: basal not rosetted, early-deciduous, 1--6(8) cm, 1--2-pinnately divided, lobes entire to lobed; mid-cauline short-petioled to +- sessile, 1.5--3.5(4.5) cm, 0.5--1.2 cm wide, gradually reduced and less divided distally, lobes entire to serrate. Inflorescence: elongated, rachis glabrous or hairs straight, cylindric. Flower: sepals 0.5--0.7(0.9) mm; petals 0.4--0.5 mm, elliptic to linear, white; stamens 2. Fruit: 1.3--1.7 mm, 2--2.5 mm wide, spectacle-shaped, flat, wingless, notch 0.2--0.4 mm; valve walls thick, tubercled, glabrous, strongly veined; style 0; pedicel spreading, 1.4--2.5(4) mm, cylindric, glabrous or hairy adaxially. Seed: 1--1.2 mm, ovate. Chromosomes: 2n=32.
Ecology: Common. Disturbed areas, fields, pastures; Elevation: < 1000 m. Bioregional Distribution: CA; Distribution Outside California: North America; native to South America, introduced worldwide. Flowering Time: Mar--Jul
Synonyms: Coronopus didymus (L.) Sm.
eFlora Treatment Author: Ihsan A. Al-Shehbaz
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botanical illustration including Lepidium didymum


Citation for this treatment: Ihsan A. Al-Shehbaz 2016. Lepidium didymum, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on October 21, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora,, accessed on October 21, 2016.

Lepidium didymum
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© 2007 Neal Kramer
Lepidium didymum
click for enlargement
© 2009 Neal Kramer
Lepidium didymum
click for enlargement
© 2007 Neal Kramer
Lepidium didymum
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© 2009 Neal Kramer
Lepidium didymum
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© 2011 Barry Breckling
Lepidium didymum
click for enlargement
© 2007 Neal Kramer

More photos of Lepidium didymum in CalPhotos

Geographic subdivisions for Lepidium didymum:
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.