Arabis amplexicaulis Edgew.

A very polymorphic species, specially in size, form of leaf, length of pedicel and hairiness. A. alticola O.E. Schulz is a smaller form of this species, with narrow leaves and smaller flowers. A. nuristanica Kitam. is also a form of this species with short pedicels and narrow leaves (but specimen with broader cauline leaves with shorter pedicel are not lacking). As a matter of fact, similar variation also occur in A. bijuga Watt, which usually has narrower leaves and short, somewhat stellate hairs on basal leaves.

The description of Arabis amplexicaulis in FRPS and the material so named that was examined by the present authors in various Chinese herbaria represent misidentifications of A. paniculata. However, the occurrence of true A. amplexicaulis in China (Xizang) is here confirmed based on Qinghai-Tibet Team 6886 (PE).

Perennial, 20-70 cm tall, erect, usually with a single flowering stem, ± hairy with simple, forked or branched hairs, often hispid below and less hairy above. Basal leaves rosulate, often large, 5-15 cm long, 1-3 cm broad, obovate-oblong or oblanceolate, stalked, often dentate with short obtuse teeth, rarely si¬nuate-toothed, apex rounded or obtuse; cauline leaves distant, sessile, ovate to ovate-oblong, (1-) 1.5-4 (-6) cm long, 0.5-3 cm broad, amplexicaul (bases often apparently slightly auricled), slightly toothed to entire; all leaves ± hispid with branched or forked hairs. Racemes (15-) 20-40-flowered, up to 25 cm long in fruit. Flowers (5-) 8-10 mm across, white; pedicels up to 15 mm long, spreading, glabrous. Sepals 4-6 mm long. Petals 7-10 mm long, 2-3.5 mm broad. Stamens 3-4:5-6 mm long. Siliquae 30-60 mm long, 1-1.5 mm broad, linear compressed, usually spreading on horizontal pedicels, acute, glabrous; valves with a distinct mid-vein; style 1-1.5 mm long with a depressed, minute stigma; seeds many in each locule, c. 1 mm long, margined.

Herbs biennial or short-lived perennial, (20-)30-60(-70) cm tall, densely to sparsely hispid or hirsute, with primarily simple subsetose trichomes to 1.7 mm, these mixed with much fewer, smaller, stalked 2-4-forked ones. Stems erect, often single from base. Basal leaves rosulate; petiole 0.5-5 cm; leaf blade lanceolate-obovate, oblong, or oblanceolate, 3-9(-11) × 1-2(-3) cm, base attenuate, margin dentate or entire, ciliate, apex obtuse or rounded. Middle cauline leaves sessile, oblong or ovate, (1-)1.5-5(-8) × 0.6-2.5(-4) cm, base cordate or amplexicaul, margin dentate or entire. Racemes ebracteate. Fruiting pedicels divaricate, 0.6-1.5 cm, slender, straight, glabrous. Sepals oblong, 4-6 × 1.2-1.5 mm, glabrous, lateral pair saccate. Petals white, oblong or narrowly oblanceolate, (0.7-)0.9-1.2 cm × 2-3.5 mm, apex obtuse. Filaments 3.5-6 mm; anthers oblong, 0.8-1 mm. Ovules 50-70 per ovary. Fruit (2.5-)3.5-6.5(-7) cm × 1-1.5 mm, erect, divaricate, or rarely reflexed; valves with a distinct midvein, torulose, glabrous; style 1-1.5 mm. Seeds brown, oblong, 1.2-1.5 × 0.8-1 mm, uniseriate, narrowly winged apically. Fl. Apr-Jun, fr. May-Jul. 2n = 16.

Afghanistan, Himalaya (Kashmir to Nepal).

Distribution: N.W. Himalayas, Pakistan and Afghanistan.

Xizang [Afghanistan, Bhutan, India, Kashmir, Nepal, Pakistan].

2300 m

Fl. Per.: May -July.

Forest margins, shady places; 1800-3200 m.