Jepson Flora Project: Jepson Interchange    

 
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Jepson Interchange (more information)
©Copyright 1993 by the Regents of the University of California
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BRASSICACEAE

MUSTARD FAMILY

Reed C. Rollins, except as specified

Annual to subshrub
Leaves generally basal and cauline, alternate, generally simple; stipules 0
Inflorescence: generally raceme
Flower bisexual; sepals 4, free; petals (0)4, free, generally white or yellow, often clawed; stamens generally (2,4)6, generally 4 long, 2 short; ovary 1, superior, chambers generally 2, septum membranous, connecting 2 parietal placentas, style 1, stigma simple or 2-lobed
Fruit: generally capsule ("silique") with 2 deciduous valves, sometimes breaking transversely or indehiscent
Seeds 1–many per chamber
Genera in family: 300+ genera, 3000+ species: worldwide, especially cool regions; some cultivated for food (especially Brassica, Raphanus ) and ornamental
Recent taxonomic note: Recently treated to include Capparaceae [Rodman et al. 1993 Ann Missouri Bot Gard 80:686–699; Rollins 1993 Cruciferae of Continental North America. Stanford Univ Press]
Family description, key to genera by Robert A. Price.

DESCURAINIA

TANSY MUSTARD

Annual, biennial, rarely per; hairs generally minute, generally multibranched, fewer simple, some glandular
Stem branched
Leaves 1–many-pinnately lobed to compound; basal often rosetted but withering
Inflorescence elongating; bracts generally 0
Flower: petals < 3 mm, yellow or whitish, blades obovate, obtuse
Fruit linear to ± obovate, straight or uneven-margined, generally ± cylindric; style < 0.8 mm or 0, stigma generally head-like, entire
Seeds: 1–2 rows per chamber, generally < 1 mm, elliptic, plump, gelatinous when wet; wing 0; embryonic root at back of 1 cotyledon
Species in genus: ± 40 species: worldwide temp
Etymology: (F. Descourain, French botanist, 1658–1740)
Reference: [Detling 1939 Amer Midl Naturalist 22: 481–520]
Relationships, characters of species difficult. May be TOXIC to livestock.

Native

D. incisa (Engelm.) Britton

Annual; hairs generally nonglandular
Stem 1, generally branched above, rarely below
Leaves: basal ± 1–2-pinnately lobed or -compound, 5–10 cm, obovate, soon withering; cauline reduced, generally simpler upward
Inflorescence elongate; hairs on axes minute, glandular and not
Flower: petals ± 2 mm, spoon-shaped, yellow
Fruit < 1 mm wide, linear to narrowly oblong, generally ± curved, cylindric, glabrous; both ends acute to acuminate; pedicel slender
Seeds: 1 row per chamber
Ecology: Open sites, scrub
Elevation: 1000–3100 m.
Bioregional distribution: Cascade Range, Transverse Ranges, Peninsular Ranges, Great Basin Floristic Province
Distribution outside California: to British Columbia, New Mexico
4 subspp. total.

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bioregional map for DESCURAINIA%20incisa being generated
 
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Retrieve Jepson Interchange Index to Plant Names entry for Descurainia incisa
Retrieve dichotomous key for Descurainia
Overlay Consortium of California Herbaria specimen data by county on this map
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