1	"Florets 2--6 per spikelet"	"Stipa mauritanica"
1	"Florets 1 per spikelet"	2
2	"Palea grooved lengthwise"	3
2	"Palea flat"	4
3	"Blade 0.8--1.5 mm wide; awns 10--16 mm"	"Stipa purpurata"
3	"Blade 0.2--0.4 mm wide; awns 15--25 mm"	"Stipa chaetophora"
4	"Leaf tips sharp, stiff; lemma awn glabrous to scabrous; fruit ribbed"	"Stipa brachychaeta"
4	"Leaf tips acute to acuminate, not both sharp and stiff; lemma awn glabrous to scabrous or hairy; fruit not ribbed"	5
5	"Lemma margins in age strongly overlapping entire length, lemma body generally bumpy throughout, tip with crown; palea 1/4--1/2 lemma, glabrous, veins 0"	6
5	"Lemma margins in age generally not or only +- overlapping at least part of length, or strongly overlapping in some species with smooth lemmas; lemma bodies generally smooth proximally, tip generally 1--2-lobed; palea 1/3 to +- > lemma, 2-veined at least proximally, generally hairy, or both lemma and palea glabrous"	9
6	"Lemma crown generally sharply constricted proximally, distinct from rest of lemma, +- 1/5 lemma, lemma body in age distally +- glabrous"	"Stipa manicata"
6	"Lemma crown gradually expanded proximally, weakly to +- distinct from lemma, < 1/6 lemma, lemma body in age distally hairy to +- glabrous, or if crown constricted proximally then lemma body hairy in age"	7
7	"Lemma crown hairs 0.3--0.6 mm, awn 12--55 mm, +- 0.1 mm diam, callus 0.4--1.6 mm, lemma body generally hairy in age; stem 0.8--1.2 mm diam"	"Stipa lepida"
7	"Lemma crown hairs 0.8--1.1 mm, awn 38--110 mm, 0.2--0.4 mm diam, callus 1.4--3.6 mm, lemma body hairy to mostly glabrous in distal 3/4 in age; stem 1--3.1 mm diam"	8
8	"Lemma body in age glabrous in distal 3/4 except on veins"	"Stipa cernua"
8	"Lemma body in age hairy throughout"	"Stipa pulchra"
9	"Floret callus 1.7--6 mm, sharp-pointed; awn 35--225 mm; perennial herb or annual"	10
9	"Floret callus 0.1--2 mm, blunt- to sharp-pointed, awn 3--80 mm; per"	13
10	"Lemma awn densely long-hairy and feather-like proximally; perennial herb"	"Stipa speciosa"
10	"Lemma awn proximally scabrous to densely hairy but neither long-hairy nor feather-like; perennial herb or annual"	11
11	"Annual, florets 4--7 mm; callus 1.7--2.3 mm; awns proximally hairy, hairs generally visible without a hand lens"	"Stipa capensis"
11	"Perennial herb; florets 7--13 mm; callus 2--4 mm; awn proximally hairy but hairs generally not easily visible without a hand lens"	12
12	"Distal awn segment 40--120 mm, wavy to curled in age; proximal stem nodes generally concealed by leaf sheaths; panicles in age generally partially enclosed in most distal sheath"	"Stipa comata var. comata"
12	"Distal awn segment 30--80 mm, straight; proximal stem nodes generally exposed; panicles in age generally fully exserted"	"Stipa comata var. intermedia"
13	"Florets <= 2.5 mm; lemma glabrous, occasionally sparsely hairy in <i>Stipa divaricata</i>"	14
13	"Florets >= 2.8 mm; lemma hairy throughout or at least in proximal 3/4"	15
14	"Leaf blade 0.5--2.5 mm wide, margins generally inrolled; panicle 5--20 cm, proximal inflorescence nodes 1--3-branched"	"Stipa divaricata"
14	"Leaf blade 2--10 mm wide, flat; panicle 10--40 cm, proximal inflorescence nodes generally 3--7 branched"	"Stipa miliacea var. miliacea"
15	"Florets +- obovoid, length generally <= 3 &times; width; lemma densely long-hairy at least in youth, awn early-deciduous"	"Stipa hymenoides"
15	"Florets elongate-ellipsoid to fusiform, length >= 4 &times; width; lemma hairy to densely hairy (partly glabrous), awn persistent or not, or if length < 4 &times; width then awn persistent and floret not densely long-hairy"	16
16	"Awns persistent, proximally densely long-hairy, at least some hairs 0.5--8 mm"	17
16	"Awns persistent or not, proximally scabrous or with hairs < 0.5 mm"	27
17	"Distal leaves on stem with ligules 3--8 mm; lemma tip 1-lobed, lobe <= 0.1 mm, thick, leathery"	"Stipa thurberiana"
17	"Distal leaves on stem with ligules 0.3--3 mm; lemma tip generally 2-lobed or lobes occasionally 0, lobes <= 1 mm, thin, membranous"	18
18	"Lemma awn bent 1 &times;, proximally densely long-hairy, feather-like, hairs 3--8 mm"	"Stipa speciosa"
18	"Lemma awn bent 2 &times;, proximally hairy, +- feather-like or not, hairs <= 2 mm"	19
19	"Awns proximally with hairs gradually, evenly decreasing in length distally, or hairs of equal length; hairs at lemma tip < or generally +- = longest proximal awn hairs"	20
19	"Awn proximally with mixed-length hairs, longer hairs mixed with shorter; hairs at lemma tip longer than most proximal awn hairs"	23
20	"Floret 8--9 mm; lemma 1.2--1.7 &times; palea; glumes 1.3--1.9 mm wide from midvein to margin"	"Stipa latiglumis"
20	"Floret 5.5--7.5 mm; lemma 1.7--2.5 &times; palea; glumes < 1 mm wide from midvein to margin"	21
21	"Distal awn segment generally densely hairy; stem 0.3--1 mm diam, internodes glabrous; glumes generally +- purple"	"Stipa occidentalis var. occidentalis"
21	"Distal awn segment generally scabrous or glabrous, occasionally densely hairy at segment base; stem 0.5--2 mm diam, internodes glabrous to densely hairy; glumes generally green"	22
22	"Proximal 2 awn segments scabrous or densely hairy, hairs of mixed lengths; lemma tip hairs > proximal awn hairs"	"Stipa occidentalis var. californica"
22	"Proximal 2 awn segments densely hairy, hairs gradually and evenly shorter towards 1st bend; lemma tip hairs +- = proximal awn hairs"	"Stipa occidentalis var. pubescens"
23	"Florets 8--9 mm; glumes 1.3--1.9 mm wide from midvein to margin"	"Stipa latiglumis"
23	"Florets 5--7.5 mm; glumes 0.6--1 mm wide from midvein to margin"	24
24	"Callus 0.5--0.7 mm; lemma 1.3--2 &times; palea; palea tip hairs generally +- 1 mm"	"Stipa nevadensis"
24	"Callus 0.8--1.2 mm; lemma 1.7--2.5 &times; palea; palea tip hairs generally < 1 mm"	25
25	"Distal awn segment generally densely hairy; stem 0.3--1 mm diam, internodes glabrous; glumes generally +- purple"	"Stipa occidentalis var. occidentalis"
25	"Distal awn segment generally scabrous or glabrous, occasionally densely hairy at segment base; stem 0.5--2 mm diam, internodes glabrous to densely hairy; glumes generally green"	26
26	"Proximal 2 awn segments scabrous or densely hairy, hairs of mixed lengths; lemma tip hairs > proximal awn hairs"	"Stipa occidentalis var. californica"
26	"Proximal 2 awn segments densely hairy, hairs gradually and evenly shorter towards 1st bend; lemma tip hairs +- = proximal awn hairs"	"Stipa occidentalisvar. pubescens"
27	"Glumes ovate to narrowly ovate, 3--6 mm; lemma awn 3.9--14 mm"	28
27	"Glumes narrowly lanceolate to lanceolate, >= 6 mm; lemma awn (4)10--80 mm"	29
28	"Leaf blade +- 0.3 mm wide, thread-like, wavy or curled; inflorescence branches appressed to main axis or not; glumes 3--4.5 mm; lemma awn 10--14 mm"	"Stipa kingii"
28	"Leaf blade 0.6--1.4 mm wide, straight, erect, generally folded; inflorescence branches +- appressed to main axis; glumes 3.5--6 mm; lemma awn 3.9--7 mm"	"Stipa exigua"
29	"Lemma evenly hairy, hairs 1.2--6 mm, hairs at lemma middle generally +- = hairs at tip of lemma body"	30
29	"Lemma glabrous or hairs 0.2--1.5(2) mm at lemma middle, distally glabrous or hairy, hairs at lemma middle generally < hairs at tip of lemma body"	33
30	"Awns early-deciduous"	"Stipa webberi"
30	"Awns persistent"	31
31	"Sheaths not flat and ribbonlike in age; blade margins generally inrolled, 0.2--0.4 mm thick, 0.5--1 mm wide when flat; awn bent 2 &times;"	"Stipa pinetorum"
31	"Sheaths flat and ribbonlike in age; blade 0.5--1.5 mm thick when margins inrolled, <= 7 mm wide when flat; awn bent 1--2 &times;"	32
32	"Awn bent 2 &times;; stem 3--6 mm diam"	"Stipa coronata"
32	"Awn bent 1 &times;; stem 0.8--2 mm diam"	"Stipa parishii var. parishii"
33	"Lemma tip hairs 2--7 mm, generally >= 1 mm > hairs at lemma middle"	34
33	"Lemma tip hairs <= 2.2 mm or 0, generally < 1 mm > hairs at lemma middle"	35
34	"Awn bent 2 &times;; stems 3--6 mm diam"	"Stipa coronata"
34	"Awn bent 1 &times;; stems 0.8--2 mm diam"	"Stipa parishii var. parishii"
35	"Distal awn segment +- wavy"	"Stipa arida"
35	"Distal awn segment straight or +- arched"	36
36	"Lemma tip 2-lobed, lobes 1--3 mm; palea >= lemma, tip 2-lobed, veins extending into lobes"	"Stipa stillmanii"
36	"Lemma tip not lobed or lobes <= 1.2 mm; palea <= lemma, tip unlobed, palea veins ending before or at palea tip"	37
37	"Lemma tip lobes thick, stiff, +- 0.1 mm; florets +- compressed"	38
37	"Lemma tip lobes membranous, 0.1--1.2 mm; florets not compressed"	39
38	"Proximal leaf sheaths, stem glabrous to hairy, not tomentose, hairs <= 0.2 mm"	"Stipa lemmonii var. lemmonii"
38	"Proximal leaf sheaths, stem tomentose, hairs 0.4--0.6 mm"	"Stipa lemmonii var. pubescens"
39	"Proximal internodes densely hairy 3--9 mm below nodes, elsewhere less densely hairy and hairs shorter"	"Stipa diegoensis"
39	"Proximal internodes glabrous or +- hairy <= 5 mm below nodes, elsewhere generally glabrous"	40
40	"Lemma (1.1)1.2--1.3 &times; palea; palea tip hairs extending beyond tip; lemma awn 12--25 mm; leaf blades 0.5--2 mm wide"	"Stipa lettermanii"
40	"Lemma 1.5--3 &times; palea; palea tip hairs generally not extending beyond tip; lemma awn 19--31 mm; leaf blades (0.5)1.2--5 mm wide"	"Stipa nelsonii var. dorei"