Flora of New Zealand Series

Type locality: "vicinity Thames". Isotype: AK, 61798, "Waitakaruru, near Thames," V. J. Cook, March, 1940. Australian specimens appear to be conspecific.

Summer-green perennial. Rhizome 3–5 mm. diam., woody, dark brown, horizontal, forming globose, ligneous tubers. Culms 70–150 cm. × 4–5 mm., triquetrous, scabrid on the angles for a short distance below infl., solitary or rarely 2 from each tuber; basal sheaths loose, membr., septate, brown. Lvs c. 45 cm. × 6–8 mm., ∞, ± = or < culms, double-folded but flattened, coriac., tapering, margins and midrib scabrid towards the tip, sheaths long, closed, coriac. Infl. a terminal, compound, irregular umbel; rays 4–6 unequal, 2–10 cm. long, bearing clusters of 1–6 spikelets, a sessile glomerule of spikelets at the base of the rays; involucral subtending bracts similar to lvs, > infl., unequal, 15–25 cm. × 3–6 mm., as many as, or 1–2 fewer than rays. Spikelets 1–1.5–(2) cm. long, ovoid or ± cylindric, dull red-brown. Glumes membr., pubescent, tips cleft or lacerate, midrib produced to a scabrid recurved awn. Hypog. bristles up to 6, us. < nut, sometimes caducous, us. red-brown, retrorsely scabrid. Stamens 3. Style-branches 3 or 2 in the same spikelet. Nut 3–4 × 2–2.5 mm., obovate, dorsiventrally compressed and plano-convex or trigonous with obtuse dorsal angle and convex sides, apiculate, greyish to us. black and shining when mature.

DIST.: N. From North Auckland southwards to lat. 38º, further south in Hawke's Bay and inland at Lake Taupo. S. Local in Nelson, Marlborough and Westland.

Saline or fresh water swamps, found inland more often than S. fluviatilis.

Both S. medianus and S. caldwellii are closely related to the widespread S. maritimus L. which has 2 style-branches and dark brown, plano-convex nuts with convex sides.