Noar Hill is a biological Site of Special Scientific Interest south of Selborne in Hampshire. It is a Nature Conservation Review site, Grade 2, and part of East Hampshire Hangers Special Area of Conservation. An area of is a nature reserve managed by the Hampshire and Isle of Wight Wildlife Trust. It forms one of the westerly outposts of the chalk hills called the South Downs, and rises to a maximum height of about 210 metres above sea-level. The western and northern flanks slope fairly gently, but the eastern and southern flanks in places reach a gradient exceeding 60%. Gilbert White, in his Natural History of Selborne, says of Noar Hill: The western flanks and much of the summit are given over to arable fields. A smaller part of the summit, 20 hectares (about 49 acres) known as High Common, is covered with downland grasses and scrub. The northern, eastern and southern flanks are covered by deciduous woodland dominated by beech. Such beechwoods on steep hills in East Hampshire are termed "hangers". High Common is the site of mediaeval chalk-workings – chalk was dug out and spread on nearby fields as fertilizer. The excavations have left an irregular network of pits and hollows of varying size, depth, and steepness. Because the ground is so uneven, High Common remained unploughed for centuries and was only used for grazing. It retains the ancient chalk downland flora which elsewhere has largely been lost. Flora The chalk-diggings not only made High Common unsuitable for ploughing, but also left bare chalk exposed. The many inclines and aspects of the disused pits provide different microclimates, all of which add to the variety of the flora. Noar Hill is noted for its calcicoles (chalk-dwelling plants). These include hairy rock-cress (Arabis hirsuta), dropwort (Filipendula vulgaris), harsh downy-rose (Rosa tomentosa), pale flax (Linum bienne), common milkwort (Polygala vulgaris), marjoram (Origanum vulgare), wild thyme (two species: large thyme (Thymus pulegioides) and mother-of-thyme (Thymus polytrichus)), eyebright (Euphrasia nemorosa), and clustered bellflower (Campanula glomerata). Small-leaved sweet-briar (Rosa agrestis) was recorded in 1978. Four bushes of box (Buxus sempervirens) growing on the landslip are considered by Dr Francis Rose to be native. Early gentian (Gentianella anglica) has been found (1951, 1988, 1994) on the bare chalk-scree. The parasitic knapweed broomrape (Orobanche elatior) is regularly recorded. Juniper (Juniperus communis) thrives; and in spring there is a beautiful display of cowslip (Primula veris). There are