Schoenus nigricans L.

Oases, Mediterranean region, Eastern desert and Sinai.

Western, Central and southern Europe, Rhodes, Cyprus, North Africa, Sinai, Palestine, Turkey, Caucasus, Iran, Afghanistan, Pakistan, Uzbekistan, Tadjikistan; introduced to South Africa, North and South America.

Foodplant / feeds on
larva of Aphanisticus pusillus feeds on Schoenus nigricans

Foodplant / saprobe
erumpent, stromatic apothecium of Drepanopeziza schoenicola is saprobic on dry, dead leaf of Schoenus nigricans
Remarks: season: 8-9

Black bog-rush is important for other plants. It provides oxygen to its surroundings which is good ground ventilation. It also absorbs calcium, which it releases when the leaves die off. This is why it is favorable for other plants to germinate where black bog-rush grows. Black bog-rush grows in thick clusters and is easy to recognize by its dark flattened button-like 'flower' standing at the tip of its stem. Rabbits like to nibble on the leaves and it is a host plant for various moths and flies.

Rhizomes short, oblique. Culms hollow, glabrous. Leaves: basal sheaths blackish, conspicuously wider than leaf blades; blades 10–40 cm × 0.8–2 mm, margins involute, smooth or scabridulous. Inflorescences loosely ovoid, 1–2 cm; bracts 1 or 2, oblique to erect, green to dark brown or black, 1–6 cm × 1–1.5 mm. Spikelets (1–)10–25, flattened, oblong-ellipsoid; rachilla wingless, ± deciduous at maturity; basal scales 2–3, sterile; floral scales 3–8, laterally veinless, medially 1-veined, oblong, apex acute, not mucronate, distally scabrellate. Flowers: perianth bristles 0–6, smooth or scabrellate; anthers linear, connective apices subulate, conspicuous; styles 0.6–1 mm; stigmas 0.5 mm. Achenes whitish, ovoid to ellipsoid, 1–1.5 × 0.9–1.2 mm, glossy, apex obtuse, smooth or barely reticulate. 2n = 54, 55.

Caespitose perennial, 25-40 cm. Rhizome short, producing tillers. Stem 1-1.5 mm diam., terete, deeply grooved, greyish green. Leaves c. half of stem length, basal; sheaths 20-100 mm, apparently all with blades, outer dark to blackish brown, stiff, glossy, inner from pale brown to greenish, one side scarious, brown or yellowish, mouth margin deeply oblique; ligule 0.3-0.5 mm; blades 0.5-1 mm diam., thick, crescentiform in transverse section with narrow adaxial surface, or channelled, greyish green, margins smooth or slightly scabrous, apex channelled, obtuse, scabrous. Inflorescence 8-15 x 5-10 mm, ellipsoid, later obconical or almost globose, composed mostly of 5-10, tightly overlapping spikes; lowest bract or, occasionally, two lowest foliose, up to 45 mm; spikes 7-9 x 1.5-2.5 mm, fusiform, compressed, 1-3 in axil of each bract, sessile or peduncle c. 1.5 mm; glumes distichous, keeled, acute, with strong, scabrous mid-nerve, brown to blackish brown, lowest two sterile, c. 4-5.5 mm, following 2-3 fertile, c. 6 mm, and uppermost 2-3 smaller, sterile. Perianth bristles 0-5, when present much shorter than the nut and not falling with it; stamens 2-3, anthers 3-4 mm. Nut 1.4-1.6 x 1-1.1 mm, widely ellipsoid or almost globose, obtusely trigonous, smooth, white, glossy.

Calif., Fla., Nev., Tex.; Mexico; Eurasia; Africa; Australia.

Distribution: C. and S. Europe from Atlantic coast to the Crimea, Caucasus, N. and S. Africa, Yemen, Israel, Lebanon, Syria, Turkey, east to Pakistan, Uzbekistan, Tadjikistan; introduced to N. and S. America.

Fl. Per.: April - June (-August).

Fruiting summer.

Damp, calcareous or alkaline grasslands; 0–2000m.

Damp slopes, by springs, small streams and rivers; to c. 2000 m.

Schoenus nigricans is a species of sedge known by the common names black bog-rush and black sedge. It is native to Eurasia, parts of Africa, Australia, and southern North America, including Mexico and the southernmost United States. It grows in many types of wetlands and other moist and alkaline habitat, including marshes, springs, seeps, peat bogs, heath, and alkali flats. This perennial plant grows in low, tight clumps 20 to 70 centimeters tall, with threadlike leaves bearing wide, dark brown ligules. The inflorescence is a small, flattened cluster of dark spikelets. The fruit is an achene coated in a hard, white shell.

Detail of mature fruiting head