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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. incana (Fisch. & C.A. Mey.) Dorn

Biennial, canescent to greenish
Stem 3–12 dm, slender, branched, with glandular hairs or not
Leaves 1.5–10 cm, widely lanceolate or oblanceolate to ovate; basal and lower cauline leaves 1–2-pinnately lobed or -compound, upper simple to 1-pinnate, entire
Flower: petals ± 2 mm, yellow
Fruit 5–25 mm, 0.5–1.5 mm wide, linear, generally straight; both ends acute; pedicel erect to ascending, 2–4(7) mm; style < 1 mm
Seeds 4–8, 1 row per chamber
Chromosomes: 2n=14
Ecology: Open sites, meadows, sagebrush, open aspen groves
Elevation: 1500–3400 m.
Bioregional distribution: Klamath Ranges, Sierra Nevada, San Bernardino Mountains, Great Basin Floristic Province
Distribution outside California: to Alaska, e N.America
Flowering time: May–Aug
Synonyms: D. richardsonii (Sweet) O.E. Schulz; D. r. subsp. viscosa (Rydb.) Detling

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