5.
Juncus filiformis
Linnaeus, Sp. Pl. 1: 326. 1753.
Thread rush
Herbs, perennial, 0.2--3.5 dm. Rhizomes widely creeping, sparingly branched, 1.5--2 mm diam., nodes closely set. Culms terete, 1 mm diam. Cataphylls several. Leaves: blade absent. Inflorescences 3--10(--12)-flowered, loosely congested, 1--2 cm; primary bract terete, nearly equaling to much longer than culm. Flowers pedicellate; bracteoles broadly ovate, tepals light brown or green, lanceolate, 2.5--4.2 mm; inner series loosely subtending capsule at maturity, slightly shorter, margins scarious; stamens 6, filaments 0.5--0.9 mm, anthers 0.5--0.7 mm; style 0.2 mm. Capsules tan, 3-locular, nearly globose, 2.5--3 x 1.8--2.1 mm, shorter than perianth. Seeds amber, 0.5--0.6 mm, not tailed. 2n = 40, 70, 80, 84.
Flowering and fruiting summer. Usually sandy, moist or wet soil along stream banks, pools, lakes or in meadow depressions, rarely in bogs, frequently hidden by larger vegetation; 0--3000 m; Greenland; St. Pierre and Miquelon; Alta., B.C., Man., Nfld. and Labr., N.B., N.S., N.W.T., Nunavut, Ont., P.E.I., Que., Sask., Yukon; Alaska, Colo., Idaho, Maine, Mass., Mich., Minn., Mont., Nebr., N.H., N.J., N.Y., Oreg., Pa., Utah, Vt., Wash., W.Va., Wis., Wyo.; Eurasia; Atlantic Islands (Iceland).
