Claspleaf Pennycress

Presently treated by Ihsan Al-Shehbaz as Microthlaspi perfoliatum (Linnaeus) F. K. Meyer (Repert. Spec. Nov. Regni Veg. 84(5-6): 453. 1973).

Herbs annual, (3-)5-28(-40) cm tall, glabrous throughout, often glaucous. Stems erect, simple or branched basally or above. Petiole of basal leaves 0.5-1.3 cm; leaf blade ovate or broadly elliptic, 0.3-2(-2.7) cm × 2-10 mm, base cuneate or attenuate, margin entire or rarely obtusely few toothed, apex rounded. Middle cauline leaves sessile, ovate-cordate or suboblong, (1-)2-4(-5.5) × (0.2-)0.5-1.5(-2) cm, base cordate-amplexicaul, margin entire or repand, apex obtuse. Fruiting pedicels (2.5-)4-6(-8) cm, slender, divaricate, straight. Sepals ovate or oblong, (0.8-)1-1.5(-1.8) × 0.5-1 mm, not saccate, margin white. Petals white, spatulate or oblong, 1.5-2.5(-3) × 0.7-1.3 mm, apex rounded. Filaments 1-1.5 mm; anthers ovate, 0.1-0.2 mm. Ovules 4-10 per ovary. Fruit obovate or rarely suborbicular, 3-5.5(-7) × 3-4(-5.5) mm, base obtuse, apex deeply emarginate and apical notch 1-1.5 mm deep; wings 1-2 mm wide apically, much narrower at base; style absent or 0.1-0.3 mm. Seeds yellow-brown, ovoid, 0.9-1.3(-1.5) × 0.7-1(-1.2) mm, smooth. Fl. and fr. Apr-Jul. 2n = 14, 28, 42.

Annual, 5-20 cm tall, erect, simple or branched from below, glabrous, Basal leaves in loose rosette, obovate, spathulate, apex rounded, shortly stalked, 1.5-3 cm long, 1-1.5 cm broad; upper leaves lanceolate, ovate, cordate, amplexicaul; all leaves glabrous, ± glaucous, entire or slightly toothed. Racemes 15-30-flowered, up to 15 cm long in fruit. Flowers c. 2.5 mm across, white; pedicels up to 8 mm long in fruit, spreading. Sepals c. 1.5 mm long, 1 mm broad. Petalss c. 2.5 mm long, 1 mm broad. Stamens c. 1.2: 1.5 mm long. Siliculae 4-6 mm long, 3-5 mm broad, obcordate-orbicular; wings narrow, smooth, not veined; stigma subsessile at the base of the apical notch; septum c. 2 mm wide; seeds 2-3 in each locule, c. 1.5 mm long, ellipsoid, yellowish-brown.

Xinjiang [Afghanistan, Kazakhstan, Pakistan, Russia, Tajikistan, Turkmenistan, Uzbekistan; N Africa, SW Asia, Europe].

Distribution: Europe, N. Africa, S.W. Asia to Afghanistan and Pakistan.

Fl. Per.: April-July.

Slopes, roadsides, waste grounds, forest margins; 400-2400 m.

Microthlaspi perfoliatum (Linnaeus) F. K. Meyer.