15. Bristles of the involucre numerous, stiff, thickened and often united at the base. Spikelets in spikes or racemes.--Species 10. Tropics and Egypt. Some have edible seeds; several are fodder-grasses. =Cenchrus= L. Bristles of the involucre fine, not thickened at the base.--Species 65. Some (especially the duchn, _P. typhoideum_ Rich.) are cultivated as cereals, as fodder, or as ornamental plants. (Including _Gymnothrix_ Beauv. and _Penicillaria_ Willd.) =Pennisetum= Pers. 16. Spikelets with 2 outer glumes and 1 flower, or with 1 outer glume and 2 flowers. 17 Spikelets with 3 outer glumes and 1 flower, or with 2 outer glumes and 2 flowers. 21 17. Spikelets containing an hermaphrodite and a male flower, arranged in panicles. Glumes awnless. Styles free.--Species 1. South-west Africa (Nama-land). =Anthaenantia= Beauv. Spikelets 1-flowered, arranged in one-sided, usually digitate or panicled spikes. 18 18. Rachis of the spike prolonged beyond the spikelets. Style 1, with 2 stigmas.--Species 3. North-west and South Africa. =Spartina= Schreb. Rachis of the spike not prolonged beyond the spikelets. Styles 2, free or shortly united. 19 19. Styles united at the base. Flowering glume papery. Upper outer glume awned. Spikelets in digitate racemes.--Species 1. East Africa. (_Stereochlaena_ Hack.) =Chloridion= Stapf. Styles free. Flowering glume cartilaginous. 20 20. Lower outer glume decurrent into a callous swelling. Flowering glume mucronate.--Species 6. Central Africa. =Eriochloa= Kunth Lower outer glume without a callus at the base.--Species 15. Tropical and South Africa. Used as fodder-, medicinal, or ornamental plants. The seeds of several species (especially those of the fundi _P. exile_ Kippist) are sometime used as food. =Paspalum= L. 21. Spikelets containing two hermaphrodite flowers. Axis of the spikelet jointed above the persistent outer glumes. Outer glumes awnless. Spikelets arranged in panicles.--Species 6. Tropics. =Isachne= R. Br. Spikelets containing a single hermaphrodite flower and sometimes also a male flower. Axis of the spikelet jointed below the outer glumes; spikelet falling as a whole. 22 22. First (lowest) outer glume awned, as well as the second. Spikelets one-flowered, directed to one side and disposed in panicles.--Species 4. Tropical and South Africa. Some are used as fodder. =Oplismenus= Beauv. First outer glume awnless. 23 23. Second outer glume apparently removed from the first by a conical or cylindrical, strongly-haired swelling at the base, usually awned or mucronate. Spikelets in panicles. 25 Second outer glume without a basal swelling. 24 24. First outer glume as large as or larger than the second, papery.--Species 1. South-west Africa to Angola. (Under _Panicum_ L.). =Leucophrys= Rendle First outer glume much smaller than the second.--Species 20. Some are used as ornamental or fodder-plants. (Including _Monachyron_ Parl. and _Rhynchelytrum_ Nees, under _Panicum_ L.) =Tricholaena= Schrad.