A clump-forming perennial herb of wet places by rivers, ponds and lakes, and in marshes, wet fields, ditches and occasionally dune-slacks and fens. It is almost always on base-rich soils, frequently on heavy clays, where it replaces J. effusus. 0-550 m (Mattergill Sike, Westmorland).
A rhizomatous, clump-forming perennial herb of saltmarshes and saline dune-slacks. It also occurs in areas subject to freshwater seepage on low, exposed rocky cliff-tops and stony sea-loch shores. It is tolerant of a wide range of salinities and soil moisture, occurring at all levels in saltmarshes and in both silty and sandy substrates. Lowland.
This Luzula-like, tufted perennial herb is found on base-poor peaty soil by streams, on lake-shores, in runnels through wet meadows, on tracks and on mineral soil in quarries. It thrives in shallow running water. Its mode of introduction is unknown. Lowland.
This diminutive, loosely tufted, spring-germinating annual occurs in seasonally wet, compacted open ground such as in gateways and on wheel tracks, less often in natural areas of erosion and in quarries, on serpentine heathland. Lowland.
A wiry, tufted perennial herb which is characteristic of wet peaty heath and moorland, raised and valley mires and upland flushes on acidic substrates. 0-1040 m (Carrantuohill, S. Kerry).
A strong, rhizomatous perennial herb growing in dense stands in fens, marshes, wet meadows, ditches and by water, usually in more base-rich conditions than any of the other jointed-rushes (sect. Septati); it also sometimes occurs in brackish water. Lowland.
A rhizomatous plant forming large dominant patches. In N. Somerset the plant grows in brackish reed-swamp in a dune system; in Stirlingshire, it occurs in a pool on reclaimed dockland. Lowland.
A slender, tufted perennial herb found in damp open ground by roads and lakes, on paths and in woodland and forest rides. 0-430 m (above Dent station, N.W. Yorks., and in the Caulderbeck Fells, Cumberland).
A small, densely tufted perennial herb found in bare or bryophyte- or lichen-rich places on mountains on shallow soil or in rock crevices, on both acidic and calcareous substrata. J. trifidus is one of the principal angiosperms of wind-swept, often almost snow-free plateau edges over c. 1000 m, but it also occupies sites that are snow-covered for several months. From 240 m on Ronas Hill (Shetland) to 1310 m in the Cairngorms.
A short, tufted, montane perennial herb of base-rich damp rocky or gravelly places, flushes and small marshes with little competing vegetation. It occupies the same habitats as the rarer J. biglumis, and often grows near or with it, but is less restricted to high altitudes, descending from 1065 m on Snowdon (Caerns.) to, formerly, 60 m in Shetland.