1	"Plants mat-forming, with above ground rhizome; spikelet 1, terminal"	2
1	"Plants tufted, with minute roots or below ground rhizome; spikelet 1 or more, terminal or pseudolateral"	3
2	"Glumes (2.4-)3.5 - 4.5 mm long; anther (1.3-)1.5 - 2.2 mm long"	"Isolepis producta"
2	"Glumes 1.5 - 3(-3.5) mm long; anther 0.4 - 1(-1.5) mm long"	"Isolepis fluitans"
3	"Spikelets pseudolateral; nutlet ellipsoid; nutlet surface minutely papillose; anther apex with no crest"	"Isolepis hystrix"
3	"Spikelets pseudolateral or terminal; nutlet shape ellipsoid/obovoid/ovoid; nutlet surface smooth, papillose or striate; anther apex with crest"	4
4	"Inflorescence proliferating; nutlet smooth or reticulate"	5
4	"Inflorescence not proliferating; nutlet papillose to tuberculate or striate"	6
5	"Culm slender, < 1.1 mm wide; glume 1.2-2 mm long"	"Isolepis inundata"
5	"Culm stout, 1.1 - 2.5 mm wide; glume 1.6 - 3 mm long"	"Isolepis prolifera"
6	"Nutlet striate"	"Isolepis hookeriana"
6	"Nutlet papillose to tuberculate"	7
7	"Style bifid; glume (2-)2.5 - 3.2 mm long"	8
7	"Style bifid or trifid; glume 0.8 - 2(-4.1) mm long"	9
8	"Bract shorter than spikelet, caducous; mucro to < 0.1 mm long, orbicular"	"Isolepis oldfieldiana"
8	"Bract longer than spikelet, persistent; mucro to 0.3 mm long, obovate"	"Isolepis cyperoides"
9	"Nutlet tuberculate or reticulate, obovoid"	"Isolepis cernua"
9	"Nutlet papillose, ellipsoid"	10
10	"Hyaline sides of glumes < 0.4 mm wide; mucro usually > 0.1 mm long"	"Isolepis australiensis"
10	"Hyaline sides of glumes > 0.4 mm wide; mucro usually < 0.1 mm long"	11
11	"Glumes not hyaline, mucro thickened, recurved"	"Isolepis stellata"
11	"Glumes hyaline with epidermal cells visible, mucro not thickened, straight"	"Isolepis congrua"