Cenchrus ciliaris L.  

A perennial, tussocky grass, 10-150 cm tall. Leaf-blades 3-25 cm long, 2-13
mm wide. Panicle cylindrical to ovoid, 2-14 cm long, 10-26 mm wide, grey,
purple or straw-coloured; inner bristles much longer than the spikelets, one of
the bristles characteristically longer and stouter than the rest, all sparsely to
densely ciliate; outer bristles filiform. Spikelets 1-4 per burr, 2-5.5 mm long;
glumes distinct, acute.