Perennial herb (sometimes woody and somewhat suffrutescent), occasionally flowering in the first year, 0.2–2 m., stiffly erect to subscandent or straggling and more or less prostrate, simple to much-branched, stems stout to very weak, distinctly to obscurely 4-angled, striate or sulcate, subglabrous to densely tomentose, the nodes more or less shrunken when dry. Leaves elliptic, oblong or ovate, acute or acuminate to almost circular and very obtuse, gradually or abruptly narrowed below, (2)5–22 (28) × 1.3–8 (10) cm., indumentum varying from subglabrous on both surfaces through subglabrous above and densely appressed-canescent below to more or less densely tomentose on both surfaces; petioles of main stem leaves 3–25( 30) mm., shortening above and below. Inflorescences at first dense, finally elongating to (5)8–34 (40) cm.; peduncles (0.6–1)1–6 (7.5) cm. long. Bracts lanceolate or narrowly deltoid-lanceolate, pale or brownish-membranous, 1.75–5(6) mm. long, glabrous. Bracteoles 1.5–4.5(6) mm., the basal wings one third to one quarter the length of the spine and more or less adnate to it (sometimes free above or tearing free), typically tapering off above but not rarely rounded or truncate. Perianth whitish or pale green to red or purple, segments 5, 3–7 (10) mm. long, the outer pair longest, narrowly lanceolate to lanceolate, very acute, with a distinct midrib and 2 obscure to distinct lateral nerves, narrowly or moderately pale-margined. Stamens 5, the filaments 1.5–4.5(6) mm. long, alternating with subquadrate pseudostaminodes. Typically the apex of the latter curves slightly inwards as a narrow, crenate or entire, often very delicate flap, while from the dorsal surface arises a fimbriate-ciliate scale extending across the width of the pseudostaminode; not rarely, however, this is reduced to a “stag's horn”process at the centre of the dorsal surface or a shallow, dentate rim, or even becomes small and filiform, or else subapical or apical so that the pseudostaminode appears simple (this usually in small forms of var. sicula). Style slender, 1–4(6) mm. long. Capsule oblong-ovoid, 1–3(5) mm. long. Seed filling the capsule, oblong-ovoid, smooth.