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.
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.
Habit: Annual, sparsely to densely hairy, +- green or canescent, glandular or not (glabrous distally). Stem: (0.8)1.3--5.7(9.2) dm, simple or branched distally, proximally, or throughout. Leaf: basal, proximal cauline 1--15 cm, 1- or 2-pinnately lobed, oblanceolate or oblong to ovate in outline; lateral lobes 4--9 pairs, dentate to pinnately lobed; ultimate lobes oblanceolate to ovate, entire or dentate; distal cauline sessile or short-petioled, lobes generally narrower. Flower: petals, bright yellow to cream. Fruit: 4--13(17) mm, 1.2--2.2 mm wide, club-shaped (broadly linear, widest distally); valves with prominent midvein, glabrous; style to 0.2 mm, generally +- absent; pedicel ascending to spreading or +- descending, 4--23 mm, straight or curved. Seed: 16--40, 0.6--0.9 mm, in 2 rows per chamber, oblong.
Note: Descurainia pinnata subsp. halictorum (Cockerell) Detling, Descurainia pinnata subsp. intermedia (Rydb.) Detling, Descurainia pinnata subsp. menziesii (DC.) Detling represent a heterogeneous mixture of intermediates within Descurainia pinnata and its hybrids with other species.