R. klotzschianus Meisn. in DC., Prodr. 14: 1856. R. dentatus sensu Hook.f., Fl. Brit. Ind. 5: 59. 1890 p.p.; Forbes in J. Linn. Soc. 26: 356. 1891; Le Comte, Fl. Gen. Indo-China 5: 10. 1910; Samuelsson in Hand,.-Mzt., Symb. Sin. 7: 168. 1929; Samuelsson in Acta Horti Gothob. 5: 1. 1930. R. nipponicus Franch. & Savat, Pl. Japan. 2: 471. 1879. R. dentatus subsp. halacsyi (limosus x pulcher) Rech., Pat.,Verh. Zool. Bot. Ges. Wien 49: 105.1899.

Annual. Stem 20-60 cm high, unbranched or branched from near the base. Basal leaves ovate-oblong from a truncate, rarely subcordate base, flat, sometimes slightly contracted above the base (panduriform), with obtuse or slightly acute apex; petiole shorter or as long as the lamina; stem leaves normally few, smaller and with shorter petioles than the basal one. Inflorescence whorls of many-flowerd, all or at least the lower and the middle ones distant, most of them supported by a leaf. Pedicels rather thin, usually slightly longer than the fruiting perigone, articulate near the base. Valves (excluding teeth) 2.5-3.5 mm broad with 3-4 teeth, 2-3 mm long, usually all grain bearing. Nut 2-2.5 mm long.

Type: "In Nepalia B (†).

Grows from plains to 3000 m, mostly in moist areas; Distribution: Afghanista, Pakistan, India, East Asia.

R. dentatus is a highly polymorphic species; represented by several (7) geographical races from SE Europe across N Africa and the warmer parts of Asia. In Pakistan it is only represented by subsp. Klotzschianus (Meisn.) Rech. f. For details see Rech. f. 1949: 116-123.