A rhizomatous perennial of shallow water or wet ground at the edges of rivers, streams, canals, lakes and ponds, in swamps, ditches and unimproved flood meadows and in marshland. It usually grows in calcareous and mesotrophic or eutrophic conditions, in areas subject to frequent flooding. It is shade-tolerant and sometimes grows under riverside trees or in wet woodland. Lowland, but formerly at 335 m at Greystoke (Cumberland).
This rhizomatous perennial herb grows in base-rich, mesotrophic and eutrophic water, often occurring in extensive stands. Its habitats include river banks, lakes and pond margins, marshy areas near streams, fen-meadows and tall-herb fen, and carr; it is notably shade-tolerant. It avoids sites subject to marked fluctuations in water level. Reproduction by seed is poor. 0-370 m (near Garrigill, Cumberland).
A tussock-forming perennial herb, mainly occurring in open fenland but also in Salix-carr where, however, its numbers may sometimes be reduced by shading and drying out. Generally lowland, but reaches 380 m at Malham Tarn (Mid-W. Yorks.).
A morphologically variable, rhizomatous perennial. In the lowlands, robust plants grow on river banks and the margins of lakes, mires and reed-swamps. In its upland sites, it is a shorter plant and often grows on deep, wet, gently sloping peat. 0-975 m (Glas Maol, Angus).
A rhizomatous perennial herb of sandy habitats, where it can be a dominant plant of fixed dunes, dune-slacks, sandy flats and on tracksides or other ruderal habitats. Though predominantly coastal, it can be locally common on dunes and heaths inland, particularly on the Lincolnshire coversands and in Breckland. It can be a rapid coloniser, spreading by far-creeping rhizomes. It is occasionally found as an alien on railway clinker. Lowland.
A perennial herb found on ungrazed faces and ledges of wet or dry calcareous cliffs. It grows in short vegetation or amongst tall herbs, or in dwarf Salix scrub. Populations are probably maintained by vegetative growth. From 550 m in Coire Ghamhnain (Main Argyll) and usually above 700 m, reaching 1095 m on Ben Lawers (Mid Perth).
This perennial herb grows in stony, calcareous, usually micaceous flushes (especially at the point of emergence of springs) and bogs, and rarely on wet mountain ledges and crags. It often grows on or amongst grassy tussocks. Formerly recorded below 600 m, it is currently known from five localities between 680 m (Ben Lawers, Mid Perth) and 1000 m (Beinn Heasgarnich, Mid Perth).
A perennial herb of well-drained montane grassland and sedge-heath, of open stony ground, in corries where snow lies late, and gullies subject to flushing. From 15 m at Tressa Ness (Shetland), but generally an upland species, reaching 1305 m on Ben Macdui (S. Aberdeen).
A perennial herb of both wet and dry acidic soils found in a wide range of habitats from lowland heaths and Nardus grassland to heather moors, rocky hillsides and mountain summits. Its preferred sites are generally open but it also occurs in shady places, including deciduous and mixed woodlands. It is also occasionally found on coastal cliffs. 0-930 m (Glyder Fach, Caerns.) and reportedly to 975 m in the Scottish Highlands.
A perennial herb found in mesotrophic fens on or near the margins of lakes, often bordering outflow streams, and always in areas which are periodically inundated. It is often subject to light grazing by cattle. Lowland.