A vigorous, rhizomatous perennial grass, basally tufted with leaves and slender inflorescence rising to over 1 m high; a weed of cultivations, rapidly occupying abandoned farmland and waste places; generally widespread over the whole of the Region, and throughout tropical and S Africa and Madagascar, and over the Middle East to tropical Australasia.The plant is variable. Five varieties have been recognised, of which FWTA, ed. 2, lists two in the African region. They merge into one another, and are more ecoforms than valid separate varieties. By its vigorous, even aggressive habit it forms near pure stands. It collects dead hamper and is very prone to fire, either accidental or intentional. Even the mature green foliage is inflammable. Fire stimulates flowering so that in a few weeks after burning a sheet-lalang area will be covered with flowering panicles. The light fluffy seeds are carried by the wind to new sites. Dispersal may also be vicariously assisted by man. It is recorded that in Sierra Leone with the opening up of the country to agriculture, its spread has been attributed to discarded pillows stuffed with the flower floss that had been used by travellers on the old, now abandoned, railway system (10). The rhizomes are tough and vigorous, and, of course, survive burning. Lalang’s troublesomeness in cultivations is that it suppresses seedlings and adversely affects tree crops. It actively competes for nutrients. There may be an element of biotic activity. The leaves with cutting edges are hostile to bare skin and the rhizomes with very sharp pointed ends spike bare feet and injure horses’ hoofs. A Fula proverb runs: ‘A man needs shoes to walk in soo’o’, and an Hausa proverb: ‘You have to go a long way round to avoid a field of tóófáá’ (8). Presence of the plant is held by the Fula of N Nigeria to indicate fertility for sorghum fields (14). It is used in India on embankments as a soil-binder (22).Eradication from cultivations is all important. Noxious chemical sprays may be effective, but hold dangers. Sodium arsenite widely used in rubber estates in Malaya is now discounted because of the risks involved. Frequent cutting to exhaust the rhizomes may serve to check growth, as also frequent mechanical cultivation, but this may result in loss of fertility. Forking and removal of the rhizomes by hand is completely effective but this is only practical if infestation is light and sporadic and the area small. Lalang is a sun-loving plant and it can be shaded out. Anogeissus leiocarpus (Combretaceae), Gmelina arborea (Verbenaceae) and Lantana camara (Verbenaceae) are recorded as being effective, but for lalang control on plantations their presence may not be desirable either where close-planting of the primary crop may be the best solution to obtaining quickly a closed canopy.The young foliage is tender and stock will browse it. Old leaves become tough and develop razor-sharp edges. They are unpalatable and will be browsed only for want of better. The sharp leaf-margins injure the tender tissue of the mouth of stock (1). They may also cause damage internally.The older culms are used for thatching in all territories. It is considered good and durable, thought in the Kissi country of Sierra Leone to be the best, and thus was deemed to be the chiefs property (10). To give adequate waterproofing the roof pitch has to be steep and the thatch appreciably thick. In Malaya a 20 cm thick thatch may be used, requiring a strong support, and it may last 2 years, or up to 6 years if very steep (7). A life-span is given as 5 years in Lower Dahomey (6). Besides use in a conventional manner, Igala in Nigeria bind the grass in rolls while still on the ground and then place the rolls on the roof (3). A sort of matting, bags, baskets and plates are made in the Region (8). It is used as litter for stall animals in Senegal (1).Aqueous extracts of the leaves and stems have shown in laboratory experiments some action on tumours (15, 18).The foliage has been tried for paper. The reports indicated considerable promise but there appears to have been a lack of determination to follow this up (7, 22, 26). W African material should be examined.The root contains sugars. A sample is reported to hold 18.8%, mainly saccharose and glucose with traces of fructose and xylose (15, 18). Malic, citric, tartaric, oxalic and acetic acids have been reported, and other substances (5, 15, 18). Attempts have been made to ferment the runners into a beer and to extract sugar and alcohol from them but without commercial success (7). The rhizomes are eaten raw by herdsmen in Lesotho (12) and Kipsigi children in Kenya chew them for the sweet flavour (11). The root is held to be galactogenic in Congo (Brazzaville) and is given to suckling women (4). It is a proven diuretic and is given in treatment for blennorrhoea and as an anti-dysenteric (13, 15–18). In Gabon it is given with a mashed banana as a diuretic (25). The pulped-up plant is added to karite butter for use as an embrocation for coughs (1, 9). Temne in Sierra Leone use it as a cough medicine (23). In southern Africa a root-preparation is used for chest colds in children (12, 26). It is regarded as a specific for hiccups in southern Africa and an indigestion remedy (26). Fula in Senegal take a decoction of the root for schistosomiasis (17). A decoction of the dried plant is taken as a gargle for sore throat, and for neuralgia in Madagascar (9). The ash is alkaline and gets put into certain (not indicated) medicaments in the Region (1, 9). In Indochina and SE Asia there are many medicinal applications (7, 26).Nine young shoots heated on a metal sheet, powdered and swallowed with palm-oil is claimed in Congo (Brazzaville) to produce an aphrodisiac effect (4).A trace of alkaloid is reported present in Nigerian material (2). Other reports also record detection of alkaloids (18, 27).The flossy flowers are collected for stuffing cushions and pillows (8, 10, 23). It has been known in Malaya that areas of sheet lalang are purposely fired to promote flowering to obtain them (7). In Kenya, Digo use the fluff as a substitute for cotton wool in treating sores (20). Chinese consider it haemostatic (26). In the Philippine Islands it is similarly used as a vulnerary to arrest bleeding and taken internally is sedative (21).The plant is invoked in an Yoruba incantation ‘to make a husband fight with his wife’ (24).