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Published In: Outlines of Botany 854, 1093, 1123. 1835. (Feb 1835) (Outlines Bot.) Name publication detail
 

Project Name Data (Last Modified On 8/26/2009)
Acceptance : Accepted
 

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BRASSICACEAE (CRUCIFERAE) (Mustard Family)

Contributed by Ihsan A. Al-Shehbaz and George Yatskievych

Plants annual or perennial herbs, rarely woody at the base or shrubby. Leaves alternate or basal, rarely opposite or whorled, lacking stipules, entire to deeply lobed or compound. Inflorescences terminal (except in some species of Lepidium), short to elongate racemes or panicles, or reduced to single, long-stalked flowers (in Leavenworthia). Flowers mostly actinomorphic, perfect. Calyces of 4 free or rarely united sepals. Corollas of 4 free petals, these uncommonly reduced or absent, often narrowed to stalklike bases. Stamens (2, 4)6, often the outer 2 shorter than the inner 4. Ovary 1 per flower, superior, of 2 fused carpels, usually with 2 locules. Style 1 per flower, persistent in the fruits, the stigma 1, entire or 2-lobed. Ovules 1 to numerous. Fruits uncommonly indehiscent and achenelike or more commonly 2-valved capsules that dehisce longitudinally leaving a persistent replum (the thin, placental band of tissue around the periphery of the septum, the partition between the 2 locules), these arbitrarily referred to as siliques when more than 3 times as long as wide or silicles when less than 3 times as long as wide. Seeds variously shaped, with curved embryos. About 350 genera, about 3,500 species, worldwide, but most diverse in temperate and alpine regions and dry areas.

The petals of most species of Brassicaceae are arranged in the shape of a cross, leading to the common name crucifer and the familial name Cruciferae. The family contains a large number of economically important species, both beneficial plants cultivated for food and oils and detrimental weeds. Although separate keys to flowering and fruiting material are given, most species flower for long enough that flowers and fruits are present at the same time. It is recommended that both keys are used, and a more reliable determination to the genus is achieved when both keys are successfully used to reach to the same genus.

An important character of the fruits is whether they are circular in cross-section, 4-angled, or slightly to strongly flattened. If flattened, they can be flattened parallel or at a right angle to the septum. In parallel-flattened fruits, the septum is a broad band of tissue between the 2 faces (valves) extending the full width of the fruit, and the replum is visible as a line along the edge of each face. In fruits flattened at a right angle, the septum is a narrow line of tissue bisecting each face, and the replum is visible as a line along the middle of the face. Such fruits sometimes also have lines or wings along the margins and are almost always shorter than 3 times as long as wide.

 

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1.All or nearly all of the flowers solitary on long stalks originating from the basal rosette
Leavenworthia
1.All flower stalks arranged in racemes or panicles
2.Stamens 2
Lepidium
2.Stamens (4)6
3.Petals absent
4.Plants with at least some branched hairs
Draba
4.Plants glabrous
Rorippa
3.Petals present
5.Petals white, pink, or purple
6.Petals deeply 2-lobed at the tip
7.Stem leaves many
Berteroa
7.Stem leaves absent
Draba
6.Petals not lobed, entire or slightly notched at the tip
8.Stems rooting from most nodes
Nasturtium
8.Stems not rooting from nodes
9.Upper stem leaves clasping or auriculate
10.Plants with at least some branched hairs
11.Ovaries triangular to obcordate in profile; stellate hairs sessile
Capsella
11.Ovaries linear in outline; stellate hairs absent or with a short-stalked base
12.Stellate hairs stalked; young fruits appressed to the axis of the inflorescence
Arabis
12.Stellate hairs absent, or if present, then the young fruits spreading in relationship to the axis of the inflorescence
Boechera
10.Plants glabrous or exclusively with simple hairs
13.Ovaries and young fruits linear in profile
Iodanthus
13.Ovaries and young fruits ovate to circular in profile
14.Ovules 2 per ovary
Lepidium
14.Ovules at least 4 per ovary
15.Stem leaves with the margins entire; crushed or bruised plants with neither an unpleasant aroma nor an odor of garlic
Microthlaspi
15.Stem leaves with the margins toothed; crushed or bruised plants usually with an unpleasant aroma or an odor of garlic
Thlaspi
9.Upper stem leaves neither clasping nor auriculate, sometimes absent
16.Plants with at least some branched hairs
17.Plants uniformly pubescent with appressed hairs each having 2 opposite branches, thus appearing as a straight line with an attachment point near the center
Lobularia
17.Plants with more than one kind of hair
18.Ovaries and young fruits linear
19.Uppermost stem leaves linear, the margins entire
Arabidopsis
19.Uppermost stem leaves ovate to lanceolate, the margins usually toothed
20.Petals white; stigmas entire; plants not glandular
Boechera
20.Petals purple or pink, rarely white; stigmas 2-lobed; plants sparsely to moderately glandular
Hesperis
18.Ovaries and young fruits oblong, elliptic, or ovate
21.Petals purple or pink; plants perennial; styles 4–8 mm long
Aubrieta
21.Petals white; plants annual; styles absent or to 0.2 mm long
Draba
16.Plants glabrous or exclusively with unbranched hairs
22.Plants with stalked glands
Chorispora
22.Plants without glands
23.Petals purple, or if pink or white, then with darker veins
24.Petal veins distinctly darker than the rest of the petal; ovaries and young fruits sessile
Raphanus
24.Petal veins not darker than the rest of the petal; ovaries and young fruits with a stalk above the receptacle (attachment point of the calyx and corolla)
Lunana
23.Petals white or if pink then the veins not darker than the rest of the petal
25.Ovaries and young fruits circular or ovate in profile
26.Ovules 2 per ovary
Lepidium
26.Ovules many per ovary
Armoracia
25.Ovaries and young fruits linear in profile
27.Plants perennial with rhizomes or tubers
Cardamine
27.Plants annual or biennial
28.Upper stem leaves broadly ovate to triangular, the margins coarsely toothed but not lobed; plants with the odor of garlic when crushed or bruised
Alliaria
28.Upper stem leaves pinnately divided
29.Young fruits with the replum winged; seeds wingless
Cardamine
29.Young fruits with the replum wingless; seeds winged
Planodes
5.Petals yellow or orange, rarely pale yellow
30.Inflorescences bracteate, at least toward the base
31.Ovaries linear in profile; petals 4–7 mm long; styles 1.5–3.0 mm long
Erucastrum
31.Ovaries oblong or elliptic in profile; petals 8–11 mm long; styles 5–10 mm long
Selenia
30.Inflorescences not bracteate
32.Petal veins distinctly darker than the rest of blade
33.Stigma 2-lobed; pistil not segmented
Eruca
33.Stigma not lobed; pistil segmented above the base into a sterile lower segment and ovulate upper segment
Raphanus
32.Petal veins not darker than the rest of blade
34.Upper stem leaves perfoliate, clasping, or auriculate
35.Plants with at least some branched hairs
36.Ovaries and young fruits linear in profile
Turritis
36.Ovaries and young fruits ovate, pear-shaped, or circular in profile
37.Petals 1.5–2.5 mm long; ovules 4 per ovary
Neslia
37.Petals 3.0–5.5 mm long; ovules 6–12 per ovary
Camelina
35.Plants glabrous or with exclusively simple hairs
38.Ovules 1 or 2 per ovary
39.Lowermost stem leaves entire or toothed
Isatis
39.Lowermost stem leave 2 or 3 times pinnately divided
Lepidium
38.Ovules more than 8 per ovary
40.Upper stem leaves entire, often glaucous
41.Pistils and young fruits beaked
Brassica
41.Pistils and young fruits not beaked
Conringia
40.Upper stem leaves toothed or pinnately lobed, not glaucous
42.Stems angled; ovules in 1 row per locule
Barbarea
42.Stems not angled; ovules in 2 rows per locule
Rorippa
34.Upper stem leaves petiolate or sessile, not clasping or auriculate
43.Plants with at least some branched hairs
44.Leaves 2 or 3 times pinnately divided; branched hairs treelike (with a stalked base and somewhat ascending branches)
Descurainia
44.Leaves entire or toothed; branched hairs stellate, sessile
45.Ovaries and young fruits linear in profile
Erysimum
45.Ovaries and young fruits circular or nearly so in profile
46.Petals 2–4 mm long; simple hairs present in addition to the branched hairs; style less than 1 mm long
Alyssum
46.Petals 5–11 mm long; simple hairs absent, the hairs all branched; styles 2–5 mm long
Physaria
43.Plants glabrous or with simple hairs only
47.Most of the leaves basal
Diplotaxis
47.Most of the leaves on the stem
48.Sepals spreading or reflexed at flowering
Sinapis
48.Sepals erect or ascending at flowering
49.Ovules 1–4 per ovary
Rapistrum
49.Ovules more than 10 per ovary
50.Plants aquatic or of wet areas; ovary and young fruits oblong in profile, rarely linear; ovules in 2 rows per locule
Rorippa
50.Plants terrestrial; ovary and young fruits linear in profile; ovules in 1 row per locule
51.Stigmas 2-lobed; uppermost leaves pinnately divided
Sisymbrium
51.Stigmas entire; uppermost leaves often toothed or entire
Brassica
 
 
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