Isatis costata C. A. Mey.

The record in FRPS and provincial Chinese floras of Isatis oblongata de Candolle is based on misidentified plants of I. costata or I. tinctoria. Isatis oblongata perhaps deserves only infraspecific rank under I. costata. Forms with glabrous or densely pubescent fruit often occur in the same population and, therefore, var. lasiocarpa does not merit recognition.

Annual or biennial, 40-120 cm tall, erect, much branched above, apparently glabrous, subglaucous. Basal leaves obovate-oblong, 8-14 cm long, 2-3 cm broad, subsessile, apex rounded, margin entire or obscurely dentate; cauline leaves a little smaller, lanceolate, auricled at base, amplexicaul, entire; all leaves glabrous or sparsely ciliately hairy with simple hairs. Racemes ± similar to the above species. Flower 3-4 mm across, yellowish. Sepals 1.5-1.7 mm long, c. 1 mm broad. Petals 2.5-3 mm long, 1.5-2 mm broad; Siliculae oblong-obovate, or oblong elliptic, 10-15 mm long, 4-6 mm broad, glabrous or minutely pubescent; apex± rounded; locules somewhat elongated, usually as long or a little longer than the upper portion of the wing, midrib ± 3-ridged; seed c. 3 mm long, 1 mm broad, oblong-ellipsoid, brown.

Differs from the previous species by its siliculae with ± rounded apex and base, not cuneate below the locule, and wall of the locule ± 3-ridged.

Herbs annual or biennial, 40-120 cm tall. Stems erect, much branched above, glabrous, slightly glaucous. Leaves glabrous or sparsely pilose. Basal leaves soon withered; petiole (0.5-)1-5 cm; leaf blade obovate-oblong, oblanceolate, or spatulate, (2-)8-9(-14) × (0.5-)1-3 cm, margin entire or dentate. Middle cauline leaves sessile; leaf blade narrowly oblong, lanceolate, or lanceolate-ovate, (1-)3-8(-11) × (0.3-)0.5-2(-3) cm, base auriculate or amplexicaul, margin entire, apex obtuse or subacute. Fruiting pedicels slender, thickened and subclavate at apex, 4-8 mm, glabrous. Sepals oblong, 1.5-1.8 × 0.5-0.8 mm, glabrous. Petals yellow, oblong-oblanceolate, 2.5-3 × 0.5-0.8(-1) mm, apex obtuse. Filaments 1-1.8 mm; anthers ovate, 0.4-0.5 mm. Fruit oblong or elliptic, rarely oblong-obovate, (0.7-)0.9-1.2(-1.5) cm × 3-5(-6) mm, broader at middle, glabrous or sparsely to densely pubescent, base and apex rounded to subacute, winged all around; locule (3-)4-6(-9) mm, usually conspicuously 3-ribbed or with a prominent midvein and 2 lateral ones, rarely 2-seeded; apical wings (1.5-)2-3.5 mm wide. Seeds yellowish brown, narrowly oblong, 2.5-3.5 × 0.9-1.3 mm. Fl. and fr. Jun-Aug. 2n = 28*.

Distribution: C.Asia, Kashmir and Pakistan.

Gansu, Liaoning, Nei Mongol, Xinjiang [Kashmir, Kazakhstan, Mongolia, Pakistan, Russia, Tajikistan].

Fl. Per.: May-August.

Mountain slopes, steppe, hillsides, roadsides; 700-2500 m.

Isatis costata var. lasiocarpa (Ledebour) N. Busch; I. costata var. leiocarpa Ledebour; I. lasiocarpa Ledebour.