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Descurainia incana

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.
Genus: DescurainiaView DescriptionDichotomous Key

Common Name: TANSY MUSTARD
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.

Descurainia incana (Fisch. & C.A. Mey.) Dorn
NATIVE
Habit: Biennial, hairy, canescent to +- green (glandular). Stem: erect, simple proximally, many-branched distally, (1.5)2.5--12 dm. Leaf: basal, proximal cauline 1.5--10(13) cm, widely lanceolate to oblanceolate or ovate, 1-pinnately lobed; ultimate segments linear to oblong or lanceolate, 3--10(15) mm, entire; distal cauline smaller, lobes narrower. Flower: sepals 1--1.8 mm, +- yellow; petals 1.2--2 mm, oblanceolate. Fruit: erect, appressed, (4)5--10(15) mm, 0.7--1.2(1.5) mm wide, linear, straight; valves glabrous; septum midveined; style 0.1--0.4 mm; pedicel erect to erect-ascending, 2--8(11) mm, straight. Seed: 14--22, in 1 row, 0.8--1.2 mm, ellipsoid to narrowly oblong. Chromosomes: 2n=14,28.
Ecology: Open sites, meadows, sagebrush scrub, open aspen groves, roadsides; Elevation: 100--3500 m. Bioregional Distribution: KR, SN, SnBr, GB; Distribution Outside California: to Alaska, Wyoming, New Mexico, Quebec, northeastern United States. Flowering Time: May--Sep
Synonyms: Descurainia richardsonii (Sweet) O.E. Schulz, illeg.; Descurainia richardsonii subsp. viscosa (Rydb.) Detling
eFlora Treatment Author: Ihsan A. Al-Shehbaz
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Citation for this treatment: Ihsan A. Al-Shehbaz 2016. Descurainia incana, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=22609, accessed on July 27, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on July 27, 2016.


Descurainia incana
click for enlargement
© 2015 Barry Breckling
Descurainia incana
click for enlargement
© 2015 Barry Breckling
Descurainia incana
click for enlargement
© 2015 Barry Breckling
Descurainia incana
click for enlargement
© 2004 Steve Matson
Descurainia incana
click for enlargement
© 2015 Barry Breckling
Descurainia incana
click for enlargement
© 2004 Steve Matson

More photos of Descurainia incana in CalPhotos


Geographic subdivisions for Descurainia incana:
KR, SN, SnBr, GB;
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.
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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.
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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.