Acid Soils have few basic minerals such as calcium and magnesium and are typically formed on rocks such as sandstones and granites.

Annual plants live for a year or less.

Base-rich or basic soils have large amounts of basic minerals (mainly calcium) and so are only slightly acid, neutral or alkaline.

Bogs occur on wet, more or less acid peat, and are often dominated by sphagnum mosses and sedges.

Calcareous soils are formed over chalk and limestone, and so are extremely base -rich. They are never more than slightly acid at the surface, and typically have a rich flora.

Casual plants appear only irregularly and are not native to the area.

Cones in horsetails and clubmosses are the fertile, spore-bearing region, more or less clearly differentiated from the stem.

Dunes are areas of wind-blown, usually calcareous shell-sand near the sea, with areas of damp ground termed 'slacks' in between.

Fens occur on base-rich peat, in contrast to bogs which are acid; the source of the bases is always infiltrating water from the surrounding land, since peat has no mineral reserves. Poor fens are nutrient-poor or acid, changing to bogs.

Heaths are dry, heather- or gorse-dominated areas in lowland regions, with rather acid soils. Wet heaths lie between bogs and heaths.

Margin is edge.

Marshes are wet habitats on mineral soils, though often with a thin layer of peat.

Moors are the upland counterpart of heaths and are typically dominated by heather, though bilberry, grasses or mosses may be important components.

Peat is a soil wholly composed of the un- or partially decomposed remains of plants which once grew on the site. It typically occurs in waterlogged conditions in which decomposition is very slow. Peats are found in fens and bogs.

Perennials are plants that survive for more than a single growing season.

Rhizomes are underground stems, from which shoots arise, sometimes swollen with stored food. They may be horizontal and far-creeping, short, or even upright.

Slack is a damp area in a sand-dune system.

Waste places are areas much disturbed by man, but not cultivated.

Wintergreen is a plant that remains green through the winter.