1	"Neither lemma nor column articulated at the summit"	2
1	"Lemma or column articulated at the summit"	5
2	"Lateral awns absent or much reduced or, if up to 13 mm long, much finer than the central awn; tip of lemma with a seni-circular bend below the column"	"Aristida abnormis"
2	"Lateral awns well developed, similar to the central awn; lemma straight"	3
3	"Plants annuals or short-lived perennial"	"Aristida adscensionis"
3	"Plants densely tufted perennials"	4
4	"Lemmas, including the callus, 6-9.5 mm long; column 6-8 mm long"	"Aristida somalensis"
4	"Lemmas, including the callus, 10-13 mm long; column absent or up to 4 mm long"	"Aristida stenostachya"
5	"Articulation at the top of the column, just below the awns"	"Aristida mutabilis"
5	"Articulation at the base of the column"	6
6	"Plants annuals"	7
6	"Plants tufted perennials"	8
7	"Glumes unequal, linear-lanceolate, long acuminate, the lower 15-25 mm long, the upper 13-20 mm lon; lemma 4-7.5 mm long"	"Aristida funiculata"
7	"Glumes subequal, linear, tapering to a fine awn, about 35 mm long including the awn; lemma about 10 mm lonh"	"Aristida leptura"
8	"Awns very unequal, the lateral awns not much more than 1/2 as long as the central awn"	9
8	"Awns about equal, the lateral awns only slightly shorter than the central awn"	11
9	"Panicles delicate, open"	"Aristida anisochaeta"
9	"Panicles dense, spikelike"	10
10	"Lemma body contracted in the upper half, smooth, 2.5-2.8 mm long; column usually less than 20 mm long"	"Aristida kelleri"
10	"Lemma body not contracted, more or less cylindrical, papillose, 3.3-4.7 mm long; column usually 20-25 mm long"	"Aristida triticoides"
11	"Panicle tightly congested, very dense"	12
11	"Panicle at most loosely contracted"	13
12	"Panicle cuneate below but enclosed by the top leaf sheath; upper glume entire; column dilated at the distal end"	"Aristida protensa"
12	"Panicle tapered below, not cuneate, fully exserted from the top leaf sheath"	"Aristida pycnostachya"
13	"Plants low-growing, densely tufted, up to 20(-25) cn tall, with much branched woody base; awns 6-7 cm long, stiff and divergent, the inflorescence comprising most of the plant's height"	"Aristida migiurtina"
13	"Plants loosely or densely tufted plants, usually more than 30 cm tall, often up to 100 cm; inflorescences much less than 1/2 the height of the plant"	14
14	"Lemma body contracted in the upper half, the narrowed portion scabrous"	"Aristida paoliana"
14	"Lemma body not contracted, more or less cylindrical"	15
15	"Plants suffrutescent, with woody, glaucous stems up to 100 cm tall and branched from the upper nodes"	"Aristida sieberiana"
15	"Plants not suffrutescent; stems wiry, up to 50 cm tall, branched only at the base"	16
16	"Awns very slender, flexuous, 9.5-10.5 cm long"	"Aristida tenuiseta"
16	"Awns 4.5-6.5 cm long"	17
17	"Upper glumes, including the awn, 25-35 mm long, the awns 1/3-1/2 as long as the body"	"Aristida schebehliensis"
17	"Upper glumes, including the awn (if present) 13-22 mm long, the awn less than 1/4 the length of the body, usually much shorter and frequently absent"	"Aristida stenophylla"