Juncus articulatus subsp. articulatus

Short- or long-rhizomatous perennial, forming tufts or swards, often red-tinged. Culms decumbent, rarely erect, new shoots often arising from nodes, to c. 50 cm high. Leaves arising from culms and creeping stems; blade hollow, with conspicuous transverse septa, usually shorter than culms, terete or slightly compressed, c. 0.5–2 mm wide, apex broadly acute to obtuse; auricles usually obtuse, up to c. 2 mm long. Inflorescence of 4–40(–60) usually discrete clusters, each with 2–13(–25) flowers, 5–9 mm wide when in fruit; primary bract shorter than inflorescence; prophylls absent. Tepal midrib green, soon becoming strongly reddish-brown, margins pale; outer tepals 2–3 mm long, acute; inner equal to or slightly shorter than outer, acute or obtuse; stamens 6, anthers 0.5–0.9 mm long. Capsules dark brown or red-brown to almost black (at least in upper half), occasionally dark golden-brown, trigonous-ovoid, 2.5–4 mm long, exceeding tepals, tapering gradually or contracted rather abruptly to a distinct mucro to c. 0.8 mm long; seeds 0.4–0.6 mm long, slightly asymmetrical, finely reticulate-patterned discernible at moderately high magnification, minutely apiculate at each end. Flowers mostly Nov.–Mar., seeds shed mostly Dec.–Jun.