Light blue-green clumps about 45-120 cm high with slender, tightlypacked stems, their basal bracts very dark red-purple, almost black below; the inflorescence of small pale clusters at the tips of up to five very slender erect branches, 1-2 branches longer than the rest and branched again; stamens 3, sometimes 4; capsule noticeably exceeding the tepals with a reddish-brown subacute top.

Herba perennis dense caespitosa. Rhizoma c. 3-4 mm diametro, bracteis parvis, purpureo-nigris obtectum. Culmi c. (20)-45-120 cm × (1)-1.5-2.3 mm, erecti, subcaerulei, parum nitidi, rugis distinctis in longitudinem lineati, medulla molli, lacunis interrupta; cataphylla basim culmorum laxe amplexa, purpureo-nigra, supra straminea. Inflorescentia multiflora, pars basi conglobata, pars in 2-5 ramulis gracilibus erecta, ex ipsis ramulis 1-2 ramuli longiores iterum divisi. Flores ad apices ramulorum glomerati. Tepala c. 1.5—2 mm longa, primo viridescentia, deinde straminea, marginibus late membranaceis, tepala exteriora rubescentia. Stamina 3 vel 4. Capsula c. 2-2.5 mm longa, tepala manifeste superans, ovoidea, supra sensim angustata, diluto-brunnea, apice saepe subfusco, subacuto.

In loosely packed clumps, often with few stems at the centre; stems 60-120 cm × (1.5)-2-4 mm, blue- or grey-green, ridged, not shining, hard, pith interrupted, rarely continuous, frequently almost wanting; basal bracts chestnut-brown below, the uppermost very lax; inflorescence manyflowered, much-branched or condensed to a globose head greater than 1.5 cm in diameter with one or more side clusters; flowers pale green; tepals 2.2-3.0 mm long; stamens 3, 4, or variable 3-6; capsule 2.3-3 mm long, light greenish brown, with rounded top.

In erect clumps; stems 30-80 cm × 1.5-3 mm, soft, grey-green, dull, prominently ridged especially just below the inflorescence, pith continuous at the base of the stem but becoming more spongy just below the inflorescence; basal bracts brownish-red, not shining; inflorescence condensed, the base of the subtending floral bract red-tinged and expanded to a wide opening through which the inflorescence emerges; tepals 2-2.5 mm long, finely pointed, red-brown; stamens 3; capsule about equal to the tepals, mucronulate.

In small clumps about 25-70 cm high, with slender, dull green or reddish stems, the pith interrupted in a regular pattern by very small lacunae; the inflorescence composed of two small clusters about 1 cm wide, one pressed against the stem, the other at the end of a longer slender branchlet (occasionally each of the two clusters has a smaller subsidiary cluster); stamens 3—4, rarely more in occasional flowers; the capsule often exceeding the tepals, chestnut-brown, often very dark at the top.

Herba perennis in parvis densisque caespitibus. Rhizoma c. 3-4 mm diametro, bracteis parvis, confertissimis, castaneis, dense obtechim. Culmi c. 25-75 cm × 0.75-1.5 mm, duri, laeves vel parvulis rugis in longitudinem lineati, atro-viridi vel rubidi, medulla interrupta lacunis minimis ordinate dispositis; cataphylla basim culmorum arete amplexa, rubro-castanea, supra rutila vel straminea. Inflorescentia floribus paucis in duobus locis sitis, 1—(2) glomerulis infra plus minusve sessilibus, 1—(2) glomerulis supra ad apicem ramuli elongati. Tepala c. 2-3 mm longa, rubro-brunnea. Stamina 3, interdum variabilia 3—6. Capsula c. 2.5—3 mm longa, plerumque tepala paullo superans, oblonga, castanea, apice saepe subfusco, obtuso, nitido.

In dense tufts; stems 30—120cm × 1-5—3mm, rather soft, bright- or yellow-green, smooth, shining, pith continuous, very spongy; basal bracts closely sheathing the stem; inflorescence many-flowered, lax, with lower branchlets curving downwards, or condensed into a rounded head; tepals 2-2.5 mm long, finely pointed, red-brown; stamens 3; capsule 2-2.5 mm long, shorter than, or sometimes equalling the tepals.

In very small, slender tufts; stems 15-30-(60) cm × 0.5-1 mm, erect, grey- or blue-green, ridged, not shining, wiry, pith interrupted by very small lacunae; basal bracts brownish pink below, closely sheathing, the uppermost 3-5 cm long; inflorescence a compact, almost spherical head about 1 cm wide, sometimes with 1-(3) lateral clusters; tepals 2.3-3 mm long, green with red-brown margins, later entirely light brown or red-brown; stamens 3; capsule 2—2.5 mm long, red-brown, usually slightly shorter than the tepals.

In tightly packed clumps; stems varying in length from 60-200 cm, (1)—2-3 mm wide, erect, wiry, bright green, smooth, shining, pith interrupted irregularly, or occasionally continuous; basal bracts dark red-brown below, the uppermost commonly loosely sheathing; inflorescence very variable, many- or few-flowered, either open with many or few branchlets, or condensed to a head greater than 1 cm wide, often with a few side clusters; tepals 1.5-2.3 mm long, greenish brown; stamens 3; capsule 1.5-2 mm long, light brown, darker at the top.

In large dense tufts; stems stiffly erect, 25-60 cm × 1—1.5—(2) mm, dull grey-green, prominently ridged, not shining, wiry, pith interrupted; basal bracts glossy, dark brown, almost black; inflorescence spreading with many lax branchlets; flowers evenly spaced along branchlets, not clustered, redbrown; tepals 2.5-3.8 mm long; stamens 6; capsule 2.5—3.3 mm long, very dark brown, distinctly mucronate.

Very tall and robust; stems 100-200 cm × 3-8 mm, light green, smooth, ± shining, rather soft, pith continuous; basal bracts loosely sheathing, light brown below; inflorescence many-flowered, often contracted to a dense head, or sometimes effuse with long branchlets; flowers pale green, later light brown; tepals 2.3—3.0 mm long; stamens 6; capsules 2.8—3.5 mm long, usually distinctly exceeding the tepals, very pale greenish brown, with rounded top.

In slender clumps; stems rather lax, spreading from the base, 25-70- (100) cm × 0.75-2 mm, bright green, smooth, shining, pith continuous; basal bracts dark red-brown, closely sheathing; inflorescence very lax; flowers rather separated along slender, more or less curved branchlets; tepals 2.5-3 mm long, greenish brown; stamens 6; capsules 2.5-3.3 mm long, usually distinctly exceeding the tepals, light brown to red-brown, the top often darker.

Very robust; stems 100-150 cm × 3.5—8 mm, smooth, yellow-green, soft, pith interrupted by large lacunae; basal bracts very loosely sheathing, often becoming flat above and up to 2.5 cm wide, dull brown towards the base; inflorescence many-flowered, much-branched, effuse; flowers green- to redbrown; tepals 2.3-2.8 mm long; stamens 3-(4); capsule usually about equal to the tepals in length, flattened and often darker brown at the top.

In dense clumps; stems 100-200 cm × 2-3 mm, tightly clumped and always erect near the base, occasionally drooping in the upper part, bluegreen, ridged, not shining, wiry or hard, pith irregularly interrupted or rarely continuous; basal bracts dark red-purple to almost black below, closely sheathing, often up to 25 cm long; inflorescence pale, many-flowered, a dense fan-shaped mass of florets evenly spaced along numerous branchlets which are pressed up against the very long subtending floral bract; tepals 1.7-2.2 mm long, white and membranous with a green midvein; stamens 3, or rarely variable 3—6; capsule 1.8—2.3 mm long, very pale brown.

In small clumps; stems 25-90 cm × 0.5-2.3 mm, blue-green, ridged, not shining, erect and wiry, pith interrupted; basal sheaths pinkish brown, rather short, closely appressed to the stem; inflorescence of up to 10 erect branches, often branched again, effuse, or clustered together forming a fan-shaped head; flowers evenly spaced and arranged more or less uni- laterally along the branchlets of the inflorescence or slightly more clustered in larger plants; tepals 2.0—2.8 mm long; stamens 3—4; capsule 2.2— 2.8 mm long, pale brown, ovoid-oblong.

Growing in densely tufted, narrow-based clumps. Stems 50—70—(100) cm × 1-1.5 mm, slender, light green, ridged, not shining, pith interrupted, or quite commonly continuous; basal bracts short, closely appressed to the stem, pale grey to light brown; inflorescence very pale, open, never clustered, with numerous flowers evenly spaced along slender, often curved branchlets; tepals 1.5-2 mm long, pale green; stamens 3; capsule 1.5-2 mm long, light brown, almost globose.