1	"Upper lemmas mucronate; spikelets plano-convex, cuspidate"	2
1	"Upper lemmas usually muticous, if shortly mucronate, the spikelets biconvex"	4
2	"Lower glumes over 2/3 the length of the spikelets"	"Urochloa trichopus"
2	"Lower glumes no more than 1/2 the length of the spikelets"	3
3	"Spikelets warty; paleas of lower florets coriaceous near the keels"	"Urochloa rudis"
3	"Spikelets not warty; paleas of lower spikelets hyaline to membranous"	"Urochloa panicoides"
4	"Inflorescence branches with flat, more or less ribbonlike, narrowly winged axes"	"Urochloa mutica"
4	"Inflorescence branches more or less 3-angled or crescentic in cross-section"	5
5	"Plants perennial"	6
5	"Plants annual"	12
6	"Spikelets in pairs or on short side branches, loosely or irregularly arranged"	7
6	"Spikelets usually single, occasionally in pairs, neatly and densely packed on the branches"	9
7	"Spikelets 7-8.5 mm long"	"Brachiaria longiflora"
7	"Spikelets 3-5 mm long"	8
8	"Blades narrowly lanceolate, with cordate bases"	"Brachiaria chusqueoides"
8	"Blades linear, bases not cordate"	"Brachiaria arida"
9	"Inflorescence branches 1-rowed; spikelets glabrous to sparsely sparsely pubescent, 4-6 mm long, obtuse to subapiculate"	"Urochloa brizantha"
9	"Inflorescence branches 2-rowed; spikelets pubescent to villous"	10
10	"Upper glumes and lower lemmas nearly always with a tranverse fringe of hairs near the tip, cartilaginous, sharply acute to subulate"	"Urochloa serrata"
10	"Upper glumes and lower lemmas without transverse fringes, membranous, acute to acuminate"	11
11	"Leaf blades not conspicuously distichous, 5-40 cm long, green, soft"	"Brachiaria lachnantha"
11	"Leaf blades conspicuously distichous, 2-7 cm long, glaucous, rigid, with thickened margins"	"Brachiaria stefaninii"
12	"Glumes separated by a distinct internode; upper lemmas coarsely rugose; inflorescence branches slender, widely spaced, secund"	"Urochloa leersioides"
12	"Glumes adjacent or, if slightly separated, the upper lemmas not coarsely"	13
13	"Some primary inflorescence branches with short secondary branches; spikelets borne in dense fascicles or on short secondary branchlets"	"Urochloa deflexa"
13	"Primary inflorescence branches usually without secondary branches but these sometimes present on the longest branches; spikelets borne singly or in pairs"	14
14	"Spikelets 1.5-2.5 mm long, not stipitate"	15
14	"Spikelets 2.5-5 mm long, sometimes stipitate"	16
15	"Spikelets silvery villous, borne singly; upper lemmas granulose"	"Brachiaria breviglumis"
15	"Spikelets glabrous, borne in pairs; upper lemmas rugose, muronulate"	"Urochloa reptans"
16	"Most spikelets borne singly, neatly 1- or 2-rowed, 4-5 mm long, hispidulous"	"Urochloa leucacrantha"
16	"Most spikelets borne in pairs, more or less loosely or irregularly arranged, glabrous to pubescent"	17
17	"At least some perdicels long that their spkelets; spikelets distant, spreading; inflorescence branches sometimes compound"	"Urochloa deflexa"
17	"All pedicels shorter than their spikelets; spikelets contiguous, appressed to the branch axes; inflorescence branchesusually simple but the longest sometimes with branchlets at the base"	18
18	"Upper glumes and lower lemmas thingly cartilaginous, usually smooth and glossy but sometimes pappilose-pubescent; spikelets 2.5-4.5 mm long"	"Urochloa ovalis"
18	"Upper glumes and lower lemmas membranous, glabrous or pubescent; spikelets 2.5-3.5 mm long"	"Urochloa ramosa"