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Descurainia
TANSY MUSTARD

Higher Taxonomy
Family: Brassicaceae (Cruciferae)View DescriptionDichotomous Key

Common Name: MUSTARD FAMILY
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.

Descurainia
Habit: Annual, biennial (perennial herb); hairs minute, many-branched, tree-like, occasionally mixed with fewer simple hairs, club-shaped glandular papillae occasionally present. Stem: generally branched distally. Leaf: petioled, finely 1--3-pinnately lobed or divided, basal generally early-deciduous; cauline similar to basal, less divided distally on stem, base not lobed. Inflorescence: elongating. Flower: sepals erect to spreading, base not sac-like; petals obovate, yellow [+- white]. Fruit: silique or silicle, dehiscent, linear, oblong, club-shaped, ellipsoid, or obovoid, not flattened, unsegmented; stigma entire. Seed: 5--100, in 1 or 2 rows, ellipsoid to oblong, plump; wing 0.
Species In Genus: 45--47 species: Eurasia, especially North America and South America, Canary Islands. Etymology: (F. Descourain, French botanist, 1658--1740) Toxicity: May be TOXIC to livestock. Note: Taxonomically difficult, most characters highly variable.
Unabridged Note: A taxonomically difficult genus due to extensive variation and continuity in most characters. The extensive interspecific hybridization, polyploidy, fertility among species, weedy tendencies of hybrids and parents, and lack of reliable morphological characters make it difficult to delimit taxa. Numerous infraspecific taxa have been recognized, but without extensive cytological, molecular, and experimental studies, recognition of narrowly defined taxa is neither practical nor useful.
eFlora Treatment Author: Ihsan A. Al-Shehbaz
Jepson Online Interchange
Key to Descurainia

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Citation for this treatment: Ihsan A. Al-Shehbaz 2016. Descurainia, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=10574, accessed on May 05, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on May 05, 2016.


Descurainia sophia
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© 2014 Steve Matson
Descurainia richardsonii
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© 2015 Barry Breckling
Descurainia pinnata subsp. glabra
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© 2010 Steve Matson
Descurainia richardsonii
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© 2015 Barry Breckling
Descurainia pinnata subsp. glabra
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© 2010 Steve Matson
Descurainia incisa var. incisa
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© 2008 Steve Matson

More photos of Descurainia in CalPhotos