Juicy perennial herb, 30–50 (80) cm. high, usually branched to form a flat top; stems erect or straggling, succulent, thick, glabrous or rarely scattered-pilose, usually translucent, green or reddish, sometimes rooting at lower nodes. Leaves spirally arranged, very rarely apparently opposite, petiolate; lamina very variable in shape and size, (3) 4·5–10 (15) × (2) 2·5–5 (7·5) cm., broadly elliptic or ovate to elliptic-oblong or ovate-oblong, subsucculent, usually translucent, dark or pale green to reddish-green on both surfaces, glabrous on both surfaces or rarely scattered-pilose beneath (mainly on the nerves), apex acute, often acuminate or cuspidate, rarely obtuse, margin crenate-denticulate, often with tentacular hairs on the apex of the crenations towards the base, base usually narrowly (but sometimes broadly) cuneate or rarely rounded and usually with the lamina running down the petiole and thus forming a narrow wing; secondary nerves 7–12 pairs, not very prominent beneath; petiole (1) 2–4·5 (6·5) cm. long, succulent, usually glabrous. Flowers in few-flowered axillary and/or terminal racemes, rarely apparently 1-flowered by reduction (but then the “pedicel” always with a small bract about the middle), very variable in colour and size, dark carmine, wine-red, pink, orange, violet, rarely white; bracts up to 6 mm. long, lanceolate-triangular, acute; pedicel 1–2·5 (3) cm. long, slender, succulent, usually glabrous. Lateral sepals (3) 4–7 × 2·25–3 mm. (in cultivated specimen sometimes slightly larger), ovate-lanceolate or lanceolate-triangular, acute, glabrous (always?), green; posterior sepal relatively small, up to 1·5 cm. long, c. 0·5 cm. deep, shallowly navicular, bluntish-keeled, abruptly constricted into the spur, distally sometimes subcaudate, usually acute or subobtuse; spur up to 4 cm. long, slender, slightly curved, usually with the end somewhat thickened, glabrous. Anterior petal up to 12 mm. long, up to 18 mm. broad (when flattened), very broadly ovate or obcordate, with the apex usually retuse to emarginate, rarely acute, dorsally very narrowly cristate; lateral united petals very deeply 2-lobed (the lobes appearing nearly separate), with the lobes nearly equal in shape and size, 10–20 × 7–15 mm. (sometimes even larger), obliquely obovate, obovate-spathulate or obovate-cuneate, with the apex rounded or sub-truncate (see t. 26 fig. 25). Ovary usually glabrous. Capsule up to 18 mm. long, broadly oblique-fusiform, glabrous. Seeds numerous, c. 1·75 × 1·5 mm., pyriform, rusty or blackish, ± densely covered with short thick hairs on papillose bases.