The Cotswolds IPA has been recognised as one of 165 Important Plant Areas in the UK. The species richness of vascular plants in broadleaved woodland and dry calcareous (limestone) grassland
The Cotswold Hills are formed of a plateau of Jurassic limestone which rises gently westward from the meadows of the upper Thames valley to a steep scarp slope in the west above the Severn valley and Evesham Vale. They are drained by short streams in deep cut wooded valleys, and a gentle dip slope which forms the headwaters of the Thames. The Cotswolds are nationally important for their rare limestone grassland habitats and for ancient beechwoods with rich flora. The IPA has been identified for the vascular plant species richness of the woodland and grassland habitats.
The limestone grasslands feature a rich flora, generally dominated by upright brome, torgrass and sheep's-fescue with quaking grass and a wide range of other flowering herbs. Typical plants include cowslips, common bird's-foot-trefoil, common rock-rose, wild thyme, yellow rattle, knapweed, harebell and field scabious, while less common species include autumn gentian and kidney vetch and many species of orchid, such as early-purple, green-winged, bee, pyramidal, greater butterfly, frog, common spotted and fragrant. Also to be found are the pasqueflower and two other nationally scarce plants which are specific to areas of short turf - the bastard-toadflax and the dwarf mouse-ear.
The beechwoods have a long history of management for timber and whilst the canopy is dominated by beech there is some ash, pedunculate oak and areas of sycamore. Understorey species include holly and yew. The field layer consists mainly of bramble, dog's mercury and ivy with wood anemone, sanicle, bluebell and enchanter's-nightshade. More local species include green hellebore, common wintergreen, bird's-nest orchid and broad-leaved helleborine. A number of nationally rare plants also occur, including fingered sedge, wood barley, stinking hellebore, yellow star-of-Bethlehem and both the red and narrow-lipped helleborine.