Rolland's Leafless Bulrush

North American plants have been distinguished as Trichophorum pumilum var. rollandii (Fernald) Beetle; differences from the Eurasian plants are elusive. The chromosome number in Europe is 2n = 78.

Easily recognized as small stoloniferous perennial with short leaf blades; in first sight it resembles Eleocharis quinqueflora, but the nuts are different; E. acicularis is much more slender and in Eleocharis leaf blades are lacking.

Plants loosely cespitose; rhizomes long, slender. Culms grooved, terete, 5–14 cm, smooth. Leaves: basal sheaths brown; distal leaf sheaths truncate to concave at mouth; blades 2–8.4 × 0.4–0.5 mm, much shorter than culms at flowering and fruiting. Inflorescences: spikelets 3–6-flowered, 3–4.6 × 1.7–2.8 mm; bracts shorter than spikelets, 1.6–2.5 mm, apex mucronate. Spikelets: scales brown, apex obtuse. Flowers: perianth bristles absent; anthers 0.8–1.5 mm. Achenes compressed trigonous to plano-convex, (1.2–)1.4–1.9 × 0.8–1.2 mm.

Perennial, 4-25 cm, forming small tufts. Rhizome short, ascending, emitting tillers and short stolons. Stem c. 0.5 mm diam. or less, trigonous above, almost terete below, smooth, greyish green. Sheaths 10-40 mm, from yellow brown to dark brown, semi-glossy, mouth margin straight; ligule c. 0.2 mm, hardly arched; blades mostly less than 20 mm, c. 0.3 mm wide, more or less appressed against stem, thick, channelled, margins smooth or finely scabrous, apex obtuse, slightly turgid, smooth. Spike 3-4 mm, fusiform or, at fruiting stage, globose; lowest glume 2.3-4 mm, erect, to c. equalling spike and inflorescence appearing lateral, mid-nerve strong, apex often obtuse and slightly turgid as in basal leaves, sides nerveless, yellow brown or brown, margins scarious; second glume sterile; upper 3-4 glumes fertile, 1.5-2.7 mm, cymbiform, mid-nerve mostly not or barely reaching apex, sides yellow brown or brown, margins widely scarious, often shed before nuts. Anther 1.5-1.7 mm. Nut 1.5-1.8 x 1-1.3 mm, ellipsoid or obovoid, trigonous, plano-convex, with abruptly contracted base and conical apex, finely reticulate, glossy, dark or black brown.

Distribution: Sporadically in Europe, Turkey, Caucasus, from S and SW Siberia south to Tadjikistan, along the Himalayas east to Nepal and W China; also in N. America [Scirpus pumilus Vahl subsp. rollandii (Fern.) Raym.].

Fl. Per.: May - July.

Moist alpine meadows, 2000-4000(-4900) m.

Fruiting summer (Jul–Aug). Moist to wet coniferous swamps, bogs, riverbanks; calciphile; 20–1500 m [3500 m, Nepal]; Alta., B.C., N.W.T., Que., Sask., Yukon; Alaska, Calif., Mont.; Europe; c Asia.

Scirpus pumilus Vahl, Enum. Pl. 2: 243. 1805; Baeothryon pumilum (Vahl) Á. Löve & D. Löve; S. alpinus Schleicher ex Gaudin; S. emergens (Norman) Fernald; S. pumilus subsp. rollandii (Fernald) Raymond; S. pumilus var. rollandii (Fernald) Beetle; S. rollandii Fernald; Trichophorum emergens Norman; T. pumilum var. rollandii (Fernald) Hultén

Scirpus pumilus Vahl, Enum. Pl. 2: 243. 1805. Eriophorella pumila (Vahl) Tan in P.H. Davis, Fl. Turk. 9:68. 1985. Baeothryon pumilum (Vahl) A. & D. Löve in Univ. Colo. Stud., Biol. 17: 14. 1965; Trichophorum atrichum Palla in Bot. Jahrb. 10: 296. 1888; Madalski, Fl. Polon. Terr. Adiac. Icon. 3,1: fig. 242a. 1979.