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.
THLASPI
PENNY-CRESS
Annual, biennial, perennial herb; hairs simple, generally 0
Stem branched or not
Leaves simple, entire to dentate; basal ± petioled; cauline sessile, clasping stem
Flower: sepals green or purple-tinged, bases not sac-like; petals 1–2 X sepals, white to purplish
Fruit obcordate or obovate to round, flat perpendicular to septum, tip rounded or notched; valves keeled, often winged
Seeds 2–8 per chamber, ± striate; wing 0; embryonic root at edges of both cotyledons
Species in genus: ± 75 species: temp, generally n hemisphere
Etymology: (Greek: to crush shield, from flat fruit or perhaps use of crushed seeds as mustard)
Reference: [Holmgen 1971 Mem NY Bot Gard 21:1–106]
| Introduced |
T. arvense L.
FAN-WEED
Annual; caudex 0
Stem 1–5 dm; branches 0–many
Leaves: basal few, 2–6 cm, short-petioled, oblanceolate, shed early; upper cauline sessile, wavy-margined to dentate, base lobed, clasping stem
Flower: sepals 1.5–2 mm; petals 3–4 mm, white
Fruit 1–1.5 cm wide, widely oblong to round, winged; tip notch 1.5–2.5 mm; pedicel spreading to upcurved, 7–15 mm, slender
Seed ± 2 mm, striate; wing 0
Chromosomes: 2n=14
Ecology: Disturbed areas, fields, roadsides
Elevation: < 500 m.
Bioregional distribution: California
Distribution outside California: N.America; native to Europe
Flowering time: May–Aug
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