African Mustard

Foodplant / spot causer
colony of Pseudocercosporella anamorph of Mycosphaerella capsellae causes spots on live leaf of Malcolmia africana

A very highly variable species in pubescence, flower size, and fruit length. Forms with subsetose and branched trichomes on the fruit (var. trichocarpa) have been recognized as variety of Malcolmia africana or as a distinct species, while those with shorter petals have been recognized as var. stenopetala. However, these forms are sporadic throughout most of the range of the species and are often found in the same population with typical plants of M. africana.

Herbs annual, (4.5-)15-30(-45) cm tall, sparsely to densely pubescent with short-stalked, forked or subdendritic trichomes sometimes mixed with simple subsetose ones, rarely glabrescent. Basal leaves soon withered, not rosulate. Middle and lower cauline leaves petiolate; petiole (0.1-)0.6-2(-3) cm; leaf blade elliptic, oblong, or oblanceolate, (0.5-)1.5-6(-10) × (0.3-)1-2.5(-3.5) cm, base cuneate, margin entire or dentate, rarely sinuate, apex acute; uppermost leaves smaller and subsessile. Racemes few to many flowered, elongated considerably in fruit; rachis straight or slightly flexuous. Fruiting pedicels thickened, as wide as fruit, 0.5-2(-4) mm. Sepals (3.5-)4-5 × 0.5-0.7 mm, caducous or persistent. Petals pink or purple, rarely white, narrowly oblanceolate, (6.5-)8-10(-12) × 1-2 mm. Filaments free, 2.5-5 mm; anthers narrowly oblong, 0.9-1.1 mm. Fruit linear, straight, quadrangular, not torulose, (2.5-)3.5-5.5(-7) cm × 1-1.3 mm; valves not veined, pubescent with coarse, forked trichomes mixed with much smaller, forked and subdendritic ones or subsetose simple ones, rarely glabrous; style obsolete; stigma conical, to 1 mm. Seeds oblong, 1-1.2 × 0.5-0.6 mm. Fl. Apr-Aug, fr. May-Oct.

Anhui, Gansu, Hebei, Henan, Jiangsu, Ningxia, Qinghai, Shaanxi, Shanxi, Sichuan, Xinjiang, Xizang [Afghanistan, India, Kashmir, Kazakhstan, Kyrgyzstan, Mongolia, Pakistan, Russia, Tajikistan, Turkmenistan, Uzbekistan; N Africa, SW Asia, Europe; naturalized elsewhere].

Fields, disturbed areas, roadsides, deserts; 700-3300 m.

Hesperis africana Linnaeus, Sp. Pl. 2: 663. 1753; Cheiranthus taraxacifolius Balbis (1814), not Stephan (1800); Fedtschenkoa africana (Linnaeus) Dvorák; F. stenopetala (Bernhardi ex Fischer & C. A. Meyer) Dvorák; F. taraxacifolia Dvorák; Hesperis laxa Lamarck; Malcolmia africana var. divaricata Fischer; M. africana var. korshinskyi Vassilczenko; M. africana var. stenopetala Bernhardi ex Fischer & C. A. Meyer; M. africana var. trichocarpa (Boissier & Buhse) Boissier; M. calycina Sennen; M. divaricata (Fischer) Fischer; M. laxa (Lamarck) de Candolle; M. stenopetala (Bernhardi ex Fischer & C. A. Meyer) Bernhardi ex Ledebour; M. taraxacifolia de Candolle; M. trichocarpa Boissier & Buhse; Strigosella africana (Linnaeus) Botschantzev; S. africana var. laxa (Lamarck) Botschantzev; S. stenopetala (Bernhardi ex Fischer & C. A. Meyer) Botschantzev; S. trichocarpa (Boissier & Buhse) Botschantzev; Wilckia africana (Linnaeus) F. Mueller; W. africana var. stenopetala (Bernhardi ex Fischer & C. A. Meyer) Grossheim; W. africana var. trichocarpa (Boissier & Buhse) Grossheim; W. stenopetala (Bernhardi ex Fischer & C. A. Meyer) N. Busch.

Malcolmia africana, or African mustard, is an annual plant from the Mediterranean Basin which has naturalized elsewhere, including much of western North America, and is invasive in Nevada and Utah. It has recently been shown to be only distantly related to Malcolmia proper and has been reclassified in the genus Strigosella.

It is an annual herb growing in a prostrate patch or clump with stiff, furry stems up to half a meter long. The mustardlike flowers are pink to lavender and yield siliques up to 6 centimeters long.