Annual (?) herb; stems up to 50 cm. high or more, simple or sparsely branched, erect or ascending from a prostrate base, glabrous or somewhat pilose, on very young parts reddish or green. Leaves spirally arranged, sessile or very shortly petiolate; lamina (2·5) 3·5–9 (11) × (1) 1·5–3 (4) cm., obovate to broadly oblanceolate or elliptic or rarely obtusely rhombic, apex acute and usually acuminate, margin coarsely crenulate-denticulate or serrate, often sparsely long-ciliate towards the base, base usually narrowly cuneate, membranous, usually intense green on the upper, greyish-green on the lower surface, pilose (rarely glabrous) on both surfaces when young — often with an increasing density towards the base, older ones glabrescent but sometimes scattered pilose beneath (mainly on the nerves); secondary nerves 4–6 pairs. Flowers axillary, solitary or in bundles of 2 or 3, purplish (as far as known); bracts up to 5 mm. long, lanceolate-triangular or subulate, acute, usually pilose; pedicels 2·75–5 cm. long, slender, pilose (usually more densely so in the lower half), glabrous or glabrescent. Lateral sepals 5–7 × 1–1·25 mm., narrowly triangular, acute, usually long-pilose along the margins; posterior sepal c. 7 mm. long, 2·5–3·5 mm. deep, shallowly and obliquely navicular, abruptly constricted into the spur, distally acute to subcaudate, usually glabrous; spur up to 35 (40) mm. long, very slender, with the end bluntish or slightly thickened, glabrous or very sparsely pilose (when young), slightly incurved (sometimes twisted?). Anterior petal up to 10 mm. high, 10–14 mm. broad (when flattened), dorsally very narrowly cristate, the crest terminating in a subacute point, glabrous (?) or with a row of long multicellular hairs along the crest. Lateral united petals 17–20 mm. long, deeply 2-lobed the symmetrical axes of the lobes forming an angle of c. 90°, usually glabrous; anterior lobe c. 17 × 8 mm., transversely semi-elliptic, distally entire rounded, with the lower edge straight or slightly curved; posterior lobe 10–15 × 13–15 mm., obcuneate, with the upper margin retuse to emarginate and with a slender mucro in the sinus. Ovary glabrous. Capsule up to 18 mm. long, fusiform, glabrous. Seeds numerous, c. 2 × 1·2 mm., obovate in outline, reddish brown, with a densely papillose surface, glabrous.
