Compilation
Duosperma subquadrangulare

Much branched perennial or shrubby herb to 75 cm tall with erect to procumbent stems, sometimes rooting at lower nodes, forming dense clumps; young stems quadrangular, subglabrous to puberulous or sericeous-puberulous and with slightly longer hairs on edges, no capitate glands, eventually with exfoliating bark. Leaves broadly elliptic-obovate to orbicular, largest 2–5≈1.3–4.5 cm (less than twice as long as wide), apex subacute to emarginate, base attenuate, decurrent to stem or with an ill-defined petiole up to 1.5 cm long, margin subentire to dentate, subglabrous to sparsely and uniformly sericeous-puberulous; stipule-sheath 0.5–1 mm long. Flowers solitary or in 3-flowered cymules (peduncles up to 5 mm long) which are arranged in narrow racemiform axillary sericeous-puberulous panicles; bracts foliaceous, gradually smaller upwards; pedicels 0.5–2 mm long, puberulous and with subsessile glands; bracteoles linear-lanceolate to obovate, up to 7 mm long, puberulous and with slightly longer ciliae, with or without subsessile (shorter than hairs) capitate glands. Calyx 5–8(–9 in fruit) mm long, puberulous and with scattered to dense subsessile (shorter than or same length as hairs) capitate glands, tube 4–5 mm long; teeth triangular, acute or subacute, dorsal 2.5–4 mm long, ventral 2–3 mm long with the free part 1–2 mm long. Corolla white to pale pink or mauve with orange patches on lower lip, 13–17 mm long, sericeous-puberulent on the outside; tube 8–10 mm long of which the throat 2–4 mm; lips 4–8 mm long; lobes oblong-obovate, 2–3.5 (upper lip) to 5 (lower lip) mm wide, retuse to truncate; palate with numerous long stiff straight hairs. Filaments 2–6 mm long, with scattered hairs and glands throughout; anthers 1.5–2 mm long, rounded, connective with sparse capitate glands. Dorsal stigma lobe about half the length of ventral. Capsule and seed not seen.