The African couch grass (Digitaria abyssinica (Hochst. ex A. Rich.) Stapf) is a tropical perennial grass. It can be erect or decumbent, trailing or creeping at the base (CABI, 2012; Quattrocchi, 2006). It has long, slender and wiry rhizomes that form a dense mat beneath the soil surface and can go deeper than 1 m. The rhizome may twine around the roots of other crops and smother them (CABI, 2012). The culms are slender, erect, up to 50-100 cm high (FAO, 2012). The leaves are linear, flat, 2-12 cm long, 3-5 mm (7-8 mm) wide, with a bluish-green colour (Quattrocchi, 2006). The inflorescence is a panicle of 2 to 25 racemes, borne along a 2-11 cm long central axis. Spikelets are paired and glabrous (FAO, 2012; Clayton et al., 2006). The fruit is an ellipsoid seed, variable in colour (FAO, 2012).
In the vegetative stage, Digitaria abyssinica can be confused with Bermuda grass (Cynodon dactylon), but Digitaria abyssinica has only 1 leaf per node instead of 2-3 for Bermuda grass (CABI, 2012). Digitaria abyssinica is one of the most noxious weeds in crops, plantations and orchards (FAO, 2012). It is palatable to cattle and can be used as a low quality pasture (CABI, 2012; FAO, 2012). It is valued as a cover and ley crop (see Environmental impact below) (FAO, 2012; Quattrocchi, 2006).
