Signal grass (Brachiaria decumbens Stapf or Urochloa decumbens (Stapf) R. D. Webster) is a high-yielding, vigorous rhizomatous and stoloniferous, medium-lived (5 years) perennial grass. It has a dense root-system with many bunched, quickly growing roots that go as deep as 2 m in the soil layers (Husson et al., 2008). Signal grass has a prostrate or decumbent habit, up to 60 cm high. Its flowering stems can however be up to 100 cm in height, arising from the stolons (Cook et al., 2005; Loch, 1977). Signal grass roots from the nodes of the stolons. The leaves are short, hairy and bright green in colour (Cook et al., 2005; Bogdan, 1977). Leaf-blades are lanceolate, 10-14 (-25) cm long x 8-10 (-12) mm wide (Husson et al., 2008; Cook et al., 2005; Bogdan, 1977). The inflorescence is a panicle with 2-7 slightly curved, 2-5 cm long racemes. The racemes are almost at right-angles to the 10-20 cm long axis (Husson et al., 2008; Cook et al., 2005). The spikelets are hairy, 4-5 mm long and borne in 2 rows along the rachis (Cook et al., 2005; Loch, 1977). 1 000 seeds weigh 3.6 g (Husson et al., 2008)
Brachiaria decumbens and Brachiaria brizantha are very similar morphologically, which has led to incorrect identifications (Miles et al., 1996). It mainly differs in its habit which is more decumbent, less tufted and forms a looser cover (FAO, 2016; Cook et al., 2005; Schultze-Kraft et al., 1992). Brachiaria decumbens cv. Basilisk originally identified as Brachiaria decumbens, was reidentified as Brachiaria brizantha (FAO, 2016).
Brachiaria decumbens is the most cultivated species of the genus Brachiaria. Unlike Congo grass (Brachiaria ruziziensis), it has no or very few diseases, the only issue might be due to spittlebug (Loch, 1977). It is a valuable forage used in permanent pastures. It is a high-yielding forage that forms low leafy stands and does well on infertile soils. It is palatable to all classes of livestock and withstands heavy grazing (Cook et al., 2005; Loch, 1977). Signal grass can be grazed, cut to be fed fresh or to be made into hay. Signal grass is also used as a cover crop to prevent erosion and to control weeds and insects (Mollot et al., 2012; Cook et al., 2005).