块茎山萮菜 kuai jing shan yu cai

Cochlearia wasabi Siebold, Verh. Batav. Genootsch. Kunst. Wet. 12: 54. 1832; Alliaria wasabi (Siebold) Prantl; Eutrema japonicum (Miquel) Koidzumi; E. koreanum (Nakai) K. Hammer; E. okinosimense Takenouchi; Lunaria japonica Miquel; Wasabia japonica (Miquel) Matsumura; W. koreana Nakai; W. pungens Matsumura; W. wasabi (Siebold) Makino.

Herbs 20-60(-75) cm tall, glabrous or sparsely pilose on upper parts; rhizomes fleshy, to 3 cm in diam. Stems erect or decumbent, simple. Basal leaves rosulate; petiole (6-)10-20(-26) cm, dilated at base; leaf blade cordate or reniform, (2.5-)6-15(-20) × (3-)6-18(-22) cm, base cordate, margin dentate, denticulate, shallowly crenate, repand, or subentire, with distinct apiculate callosities terminating ultimate veins, apex rounded or obtuse. Middle cauline leaves with petioles 1-5(-8) cm; leaf blade broadly ovate to ovate-cordate, 1.5-4(-6) × 2-4(-6) cm, palmately veined, base and margin as in basal leaves, apex acute. Infructescence lax raceme, bracteate throughout or basally. Fruiting pedicels ascending or divaricate, slender, 1-3.5(-5) cm. Sepals oblong, 3-4 × 2-2.5 mm, caducous. Petals white, oblong-spatulate, 6-8(-9) × 2-3 mm. Filaments white, 3.5-5 mm; anthers oblong, 0.6-0.8 mm. Ovules 6-8 per ovary. Fruit linear, 1-2 cm × 1.5-2 mm, terete, torulose; valves with an obscure midvein; gynophore (1-)2-5 mm; septum usually complete; style 2-3 mm. Seeds oblong, plump, 2-3 × 1-1.5 mm. Fl. Mar-May, fr. May-Jun.

Cultivated, also naturalized in wet areas along streams in mountains; near sea level to 2500 m. Taiwan [native to Japan, Korea, ?Russia (Far East)].

This species is cultivated for its edible rhizomes, which are the source of the pungent condiment wasabi.