An annual of docks, rubbish tips and waste ground, where it arises from wool shoddy, bird-seed, esparto and grain. Lowland.
A perennial herb of open woodlands, wood-borders, hedge banks and trackways on thin soils overlying calcareous rock. Lowland.
An annual found in arable fields, on waste ground and occasionally in gardens. It is usually casual but sometimes persists for several years, and originates as a contaminant of grain and oil-seed. Lowland.
A summer- or winter-annual of arable fields, allotments and gardens, waste ground and road verges, usually on non-calcareous soils. It occurs on limestone outcrops in W. Ireland. Generally lowland, but reaching 380 m near Simonsbath (S. Somerset).
A stoloniferous perennial herb found as a garden escape, throw-out or, occasionally, a relic of cultivation. It is often persistent on roadsides, rubbish tips, waste ground and in quarries. Lowland.
A biennial or short-lived perennial herb of woodland margins, grassy banks, ancient hedgerows and green lanes overlying oolitic limestone; occasionally recorded from stony fields and quarries. The reappearance of plants following disturbance and scrub clearance suggests that seeds remain viable over long periods. Lowland.
A perennial herb of hedge banks, grassland, heaths, open woods and woodland rides and margins. It is occasionally found in cliff-top grassland, sometimes as the genetically dwarf var. nana. It favours mildly acidic soils, but is also found on those that are neutral or somewhat calcareous. 0-460 m (Teesdale, Westmorland).
A perennial herb of damp places. It grows by streams, rivers, ditches and ponds, in fens, marshes and swamps, on rough ground and occasionally in cultivated fields. It is typically found on intermittently flooded and poorly drained soils. 0?540 m (Moor House, Teesdale, Westmorland).
A sterile rhizomatous perennial herb occurring in the habitats of either parent, but frequently in the absence of both. It grows besides streams, on river banks and roadsides, on the edge of woodland, on waste ground and as a weed of cultivated ground, particularly in the north and west where it occurs in the absence of S. sylvatica. It reproduces by rhizome fragments. 0?300 m (Pentre Llyncwmmer, Cards.).
A perennial herb naturalised on waste ground at Barry Docks (Glamorgan) and found as a casual elsewhere. Its vector is unknown. Lowland.