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Plants perennial; bisexual; usually densely to loosely cespitose, with or without rhizomes, occasionally stoloniferous. Culms 5-150(275) cm, usually glabrous and smooth throughout, sometimes scabrous or densely pubescent below the inflorescences. Sheaths from open to the base to closed almost to the top, in some species sheaths of previous years persisting and the blades usually deciduous, in other species the senescent sheaths rapidly shredding into fibers and decaying between the veins and the blades not deciduous; collars inconspicuous, usually glabrous; auricles absent; ligules 0.1-2(8) mm, membranous, sometimes longest at the margins, usually truncate, sometimes acute, usually ciliate, sometimes erose; blades flat, conduplicate, involute, or convolute, sometimes glaucous or pruinose, abaxial surfaces usually glabrous or scabrous, sometimes puberulent or pubescent, rarely pilose, adaxial surfaces usually scabrous, sometimes hirsute or puberulent, with or without ribs over the major veins; abaxial sclerenchyma tissue varying from longitudinal strands at the margins and opposite the midvein to adjacent to some or all of the lateral veins, longitudinal strands sometimes laterally confluent with other strands into an interrupted or continuous band, sometimes reaching to the veins and forming pillars; adaxial sclerenchyma tissue sometimes present in strands opposite the veins at the epidermis, the strands sometimes extending to the veins and, in combination with the abaxial sclerenchyma, forming girders of sclerenchyma tissue extending from one epidermis to the other at some or all of the veins. Inflorescences usually open or contracted panicles, sometimes reduced to racemes, usually with 1-2(3) branches at the lower nodes; branches usually erect, spreading to widely spreading at anthesis, sometimes the lower branches reflexed; Spikelets with (1)2-10 mostly bisexual florets, distal florets reduced or abortive; rachillas usually scabrous or pubescent, sometimes smooth and glabrous; disarticulation above the glumes, beneath the florets. Glumes subequal or unequal, usually exceeded by the florets, ovate to lanceolate, acute to acuminate; lower glumes from shorter than to about equal to the adjacent lemmas, 1(3)-veined; upper glumes 3(5)-veined; calluses usually wider than long, usually glabrous and smooth, sometimes scabrous, occasionally pubescent; lemmas usually chartaceous, sometimes coriaceous, bases more or less rounded dorsally, slightly or distinctly keeled distally, veins 5(7), prominent or obscure, apices acute to attenuate, sometimes minutely bidentate, usually terminally or subterminally awned or mucronate; paleas from shorter than to slightly longer than the lemmas, veins sparsely to densely scabrous-ciliate, intercostal region usually smooth and glabrous at the base, usually scabrous and/or puberulent distally, bidentate; anthers 3; ovaries glabrous or with hispidulous apices, hairs persisting on the mature caryopses. Caryopses obovoid-oblong, adaxially grooved, usually free of the lemmas and paleas, sometimes adhering along the groove, sometimes adhering more broadly; hila linear, from 1/2 as long as to almost as long as the caryopses. x=7.
Contents
Distribution
Conn., N.J., N.Y., Wash., B.C., W.Va., Wis., Ala., Ariz., Calif., Colo., D.C, Del., Ga., Pacific Islands (Hawaii), Iowa, Idaho, Ill., Ind., Ky., Md., Maine, Mich., Minn., Mont., N.Dak., Nebr., N.Mex., Nev., Oreg., Pa., S.C., Vt., Alaska, Mass., N.H., R.I., Fla., Wyo., Kans., Tex., La., Miss., Tenn., N.C., S.Dak., Utah, Va., Ark., Okla., Alta., Greenland, Man., N.B., Nfld. and Labr., N.S., N.W.T., Nunavut, Ont., P.E.I., Que., Sask., Yukon, Ohio, Mo.
Discussion
Festuca is a widespread genus, probably having more than 500 species. The species grow in alpine, temperate, and polar regions of all continents except Antarctica. There are 37 species native to the Flora region, 2 introduced species that have become established, and 5 introduced species that are known only as ornamentals or waifs. One species, E rubra, is represented by both native and introduced subspecies.
Many native species provide good forage in western North American grasslands and montane forests. Important cultivated species include Festuca rubra, grown for forage and as a turf grass, and F. trachyphylla, used as a turf grass and for erosion control. Both these species have been widely introduced to many parts of the world. A number of species are cultivated as ornamentals—including F. amethystina L., F. cinerea Vill., F. drymeia Mert. & W.D.J. Koch, F. elegans Boiss., F. gautbieri (Hack.) K. Richt., F. glauca Vill., F. kasmiriana Stapf, F. mairei St.-Yves, F. muelleri Vickery, F. pollens Host, F. pseudoeskia Boiss., F. rupicaprina (Hack.) A. Kern., F. spectabilis Jan, and F. varia Haenke. These species have not become established in the Flora region; only F. amethystina and F. glauca are included in this account.
The distribution of some taxa that are grown for turf, revegetation, and, to a lesser extent, horticulture—such as Festuca rubra subsp. rubra, F. trachyphylla, F. filiformis, and F. valesiaca—is continually expanding because of their wide commercial availability. The occurrence of these in the Flora region is no doubt much more extensive than current herbarium collections indicate.
The taxonomy of the genus is problematic and contentious, and this treatment is far from definitive. Keying the species ultimately relies on characters that are sometimes difficult to detect on herbarium specimens, such as ovary pubescence and leaf blade sclerenchyma patterns. Because of the intraspecific variability in many characters, combinations of overlapping characters must be employed for identification.
The distribution of sclerenchyma tissue within the vegetative shoot leaves is often an important diagnostic character in Festuca. Taxa in a small region can often be identified reliably without resorting to consideration of these patterns but, for the Flora region as a whole, their use is essential. These patterns should be observed in cross sections made from mature, but not senescent, leaves of vegetative shoots, xh to halfway up the blades; they can be made freehand, with a single-edged razor blade. Sections are best viewed at 40x or greater magnification, and with transmitted light (polarized if possible). Important features seen in the blade cross section are identified in Fig. 1, p. 390.
There are five main sclerenchyma distribution patterns in Festuca (Fig. 2, above). Almost all species have a strand of sclerenchyma tissue along the margins and opposite the midvein against the abaxial epidermis (Fig. 2C). Strands may be narrow (about as wide as the adjacent veins or narrower, Fig. 2D) to broad (wider than the adjacent veins, Fig. 2E). Additional strands are often present at the abaxial surface opposite the veins; these strands may be confluent (Figs. 1, 2E), sometimes combining to form a cylinder around the leaf and appearing as a continuous ring or band in the cross sections (Figs. 2F, I). Some species have additional strands on the adaxial surface opposite some or all of the veins (Figs. 2G, H). Another variant is for the abaxial sclerenchyma strands to extend inwards to some or all of the vascular bundles (veins), forming pillars in the cross sections (Figs. 2H, I). If both the abaxial and adaxial strands extend inward to the vascular bundles, they are said to form girders (Figs. 2A, B, I).
Some of the patterns described may co-occur within a leaf. For instance, some veins may be associated with pillars, others with girders; some sclerenchyma strands within a leaf may be confluent, whereas others are not. Although there may be considerable variation in the extent of sclerenchyma development, the general pattern within a species is usually constant. It is this that makes such patterns useful diagnostic characters, particularly for those needing to identify plants in vegetative condition. They have not, however, been examined for all species.
Descriptions of leaf blades are based on the leaves of the basal vegetative shoots, where present. For those without basal tufts of vegetative shoots, the cauline leaves are described. Width measurements are provided for leaves that are usually flat, or almost so, when encountered in the field or herbarium. "Diameter" is given for leaves that are usually folded or conduplicate when encountered; for leaves that are oval in cross section when folded, it is the largest diameter (or width).
Closure of the leaf sheaths should be checked on young leaves, because the sheaths often split with age, leading to underestimations of the extent of their closure. The fraction of the leaf sheath that is closed varies within and between species of Festuca, but the species can be divided into three categories in this regard: those such as F. rubra, in which the leaves are closed for at least 3/4 their length; those such as F. saximontana, in which they are closed from 1/3 to slightly more than 1/2 their length; and those such as F. tracbypbylla, in which they are not closed or closed for less than 1/4 their length. The descriptions indicate to which of these categories each species belongs. Lemma awns tend to be longer, and should be measured, on the distal florets within a spikelet.
Under adverse conditions, many species may proliferate vegetatively, where leafy bulbils or shoots form in place of some or all spikelets. Some populations of Festuca are largely (or completely) sterile, reproducing almost entirely through such bulbils, a process termed pseudovivipary. Pseudoviviparous plants may be common or even abundant in certain areas and habitats. Since these stabilized forms are largely reproductively isolated, often of unusual ploidy, and largely morphologically distinct, they are treated as separate species. Although the lower bracts in pseudoviviparous spikelets are usually more or less normal in form, they are sometimes elongated or distorted, as are the upper bracts.
Selected References
Lower Taxa
Keys
| 1 | Blades usually flat, sometimes loosely conduplicate or convolute, 1.8-10 mm wide; sheaths closed to about 1/2 their length, never about 3/4 their length; sclerenchyma girders or pillars associated with at least some of the major veins; ovary apices usually pubescent, rarely glabrous; plants rarely pseudoviviparous [for opposite lead, see p. 395]. | > 2 |
| 2 | Primary and secondary inflorescence branches stiffly and strongly divaricate at maturity, angles densely scabrous or ciliate; spikelets with 2(3) florets | Festuca dasyclada |
| 2 | Primary inflorescence branches lax or stiff, erect to ascending or spreading at maturity, sometimes lax, secondary branches not stiffly divaricate, angles smooth or scabrous; spikelets with 2-6(10) florets. | > 3 |
| 3 | Lemma awns (1.3)1.5-20 mm long, occasionally absent [for opposite lead, see p. 394]. | > 4 |
| 4 | Lemma awns usually less than 1/3 the lemma length, rarely absent; anthers (3)4-8.5 mm long; plants densely cespitose | Festuca californica |
| 4 | Lemma awns usually more than 1/3 the lemma length; anthers 1.5-5.7 mm long; plants usually loosely cespitose, rarely densely cespitose. | > 5 |
| 5 | Lemma calluses longer than wide, pubescent, at least basally; awns flexuous or kinked | Festuca subuliflora |
| 5 | Lemma calluses wider than long, glabrous, sometimes slightly scabrous; awns usually straight or slightly curved, bent or kinked. | > 6 |
| 6 | Anthers 1.5-3 mm long; lemmas entire, glabrous, sometimes sparsely scabrous; awns terminal, (2.5)5-15(20) mm long; leaf blades 3-10 mm wide | Festuca subulata |
| 6 | Anthers (3)3.4-5.7 mm long; lemmas bidentate or entire, puberulent or scabrous; awns subterminal or terminal, 1-5(8) mm long, occasionally absent; leaf blades usually less than 6 mm wide. | > 7 |
| 7 | Upper glumes 3-4.6 mm long; lemma awns (1.5)2-5(8) mm long; blades 1.8-6 mm wide, blades of the vegetative shoots narrower than the cauline blades, usually flat or convolute or loosely conduplicate; plants of forests, usually below 500 m | Festuca elmeri |
| 7 | Upper glumes (4)5.5-7(8) mm long; lemma awns 1-3(3.5) mm long; blades 1.5-3 mm wide, the vegetative shoot and cauline blades similar in width, usually loosely conduplicate, or sometimes flat; plants of subalpine and low alpine habitats | Festuca washingtonica |
| 3 | Lemmas unawned, mucronate, or with awns shorter than 2 mm [for opposite lead, see p. 393]. | > 4 |
| 8 | Ligules 2-9 mm long; lemmas unawned, sometimes mucronate, mucros to 0.2 mm long. | > 9 |
| 9 | Rhizomes present; blades with (5)7-9 veins; lemmas 4-6.5 mm long, unawned; anthers 1.5-2.6 mm long | Festuca ligulata |
| 9 | Rhizomes absent; blades with 9-15 veins; lemmas 6-10 mm long, unawned, sometimes with a mucro to 0.2 mm long; anthers 3-4.5 mm long | Festuca thurberi |
| 8 | Ligules 0.1-1.5(2) mm long; lemmas awned, mucronate, or unawned. | > 9 |
| 10 | Lemmas 3-5(5.2) mm long, unawned; anthers (0.7)1-2(2.5) mm long. | > 11 |
| 11 | Inflorescence branches usually reflexed at maturity; spikelets not or only slightly imbricate, elliptic to ovate; upper glumes 3-4(4.7) mm | Festuca subverticillata |
| 11 | Inflorescence branches ascending to spreading at maturity; spikelets closely imbricate, elliptic to obovate; upper glumes (3.5)4-5(5.5) mm | Festuca paradoxa |
| 10 | Lemmas (4.8)5-12 mm long, unawned or with awns to 2 mm long; anthers 1.6-6 mm long. | > 11 |
| 12 | Senescent sheaths not persistent, rapidly shredding into fibers; plants loosely cespitose; cauline nodes usually exposed. | > 13 |
| 13 | Lower glumes 4-7 mm long; lemmas smooth and glabrous, apices sometimes sparsely scabrous, unawned, sometimes mucronate | Festuca versuta |
| 13 | Lower glumes 1.5-4.5 mm long; lemmas scabrous or puberulent, unawned or awned, awns to 2 mm long | Festuca sororia |
| 12 | Senescent sheaths persistent or only slowly shredding into fibers; plants densely cespitose; cauline nodes usually not exposed. | > 13 |
| 14 | Panicle branches more or less erect, stiff; abaxial sclerenchyma forming continuous or interrupted bands; lower glumes from shorter than to about equal to the adjacent lemmas. | > 15 |
| 15 | Spikelets with 2-3(4) florets; glumes about equaling or slightly exceeding the upper florets; lemmas 5.5-8(9) mm long | Festuca hallii |
| 15 | Spikelets with (3)4-5(7) florets; glumes exceeded by the upper florets; lemmas (6.2)7-8.5(10) mm long | Festuca campestris |
| 14 | Panicle branches lax, loosely erect, spreading, recurved, or reflexed; abaxial sclerenchyma in strands about the same width as the adjacent veins, not forming a continuous or interrupted band; lower glumes distinctly shorter than the adjacent lemmas. | > 15 |
| 16 | Senescent sheaths persistent, not shredding into fibers; blades deciduous; spikelets lustrous; ovary apices usually sparsely pubescent, rarely glabrous; plants densely cespitose | Festuca altaica |
| 16 | Senescent sheaths persistent or slowly shredding into fibers; blades not deciduous; spikelets not lustrous; ovary apices usually densely pubescent, sometimes sparsely pubescent; plants loosely to densely cespitose. | > 17 |
| 17 | Blades of the lower cauline leaves much shorter and stiffer than those of the upper cauline leaves; lemmas smooth or slightly scabrous, unawned or the awns to 1.5(2) mm long | Festuca viridula |
| 17 | Blades of the lower cauline leaves similar in length and stiffness to those of the upper cauline leaves; lemmas scabrous or puberulent distally, the awns usually longer than 1 mm, rarely absent | Festuca washingtonica |
| 1 | Blades usually conduplicate or folded and less than 2.5 mm in diameter, sometimes convolute or flat, sometimes the leaves of the vegetative shoots conduplicate and the cauline leaves more or less flat, up to 6(7) mm wide when flat; sheath closure varied, from completely open to closed for about 3/4 their length, if the blades 2+ mm wide then the sheaths closed for about 3/4 their length; sclerenchyma girders usually absent, present if the blades 3+ mm wide, pillars sometimes present; ovary apices pubescent or glabrous; plants sometimes pseudoviviparous [for opposite lead, see p. 393]. | > 2 |
| 18 | Collars usually pubescent, at least at the margins, sometimes glabrous; lemmas (7)7 5-11 mm long, scabrous or pubescent; spikelets not pseudoviviparous; ovary apices densely pubescent | Festuca californica |
| 18 | Collars glabrous; lemmas 2-10(11) mm long, smooth or scabrous, glabrous or with hairs; spikelets sometimes pseudoviviparous; ovary apices glabrous or pubescent or ovaries not developed. | > 19 |
| 19 | Ligules 2-9 mm long. | > 20 |
| 20 | Rhizomes present; blades with (5)7-9 veins; lemmas 4-6.5 mm long, unawned; anthers 1.5-2.6 mm long | Festuca ligulata |
| 20 | Rhizomes absent; blades with 9-15 veins; lemmas 6-10 mm long, unawned, sometimes with a mucro to 0.2 mm long; anthers 3-4.5 mm long | Festuca thurberi |
| 19 | Ligules to 1.5(2) mm long. | > 20 |
| 21 | Most or all spikelets pseudoviviparous; anthers and ovaries usually absent or abortive. | > 22 |
| 22 | Rhizomes present; sheaths closed for about 3/4 their length or more, senescent sheaths rapidly shredding into fibers. | > 23 |
| 23 | Cauline blades 0.3-1 mm wide, conduplicate or folded; inflorescences sometimes racemose or subracemose, with 1-3 spikelets on the lower branches; plants of boreal and alpine eastern North America | Festuca prolifera |
| 23 | Cauline blades 1.4-2.5 mm wide, flat; inflorescences paniculate, with 2-5 spikelets on the lower branches; plants known only from the Queen Charlotte Islands | Festuca pseudovivipara |
| 22 | Rhizomes absent; sheaths closed for less than 3/4 their length, senescent sheaths sometimes persistent, sometimes shredding into fibers. | > 23 |
| 24 | Abaxial sclerenchyma in broad, sometimes confluent strands that together cover 1/2 or more of the abaxial surface; glumes densely pubescent throughout; inflorescences 1.5-10 cm long | Festuca frederikseniae |
| 24 | Abaxial sclerenchyma in narrow strands that together cover less than 1/2 the abaxial surface; glumes glabrous or pubescent; inflorescences 1-4.8 cm long | Festuca viviparoidea |
| 21 | No spikelets pseudovivaparous; anthers and ovaries well developed. | > 22 |
| 25 | Glumes about equaling or slightly exceeding the upper florets; lemma awns absent or 0.5-1.3 mm long; anthers 4-6 mm long | Festuca hallii |
| 25 | Glumes distinctly exceeded by the upper florets; lemma awns various; anthers 0.3-6 mm long. | > 26 |
| 26 | Rhizomes usually present; sheaths of the vegetative shoots closed for about 3/4 their length, glabrous or pubescent, hairs retrorse or antrorse, senescent sheaths rapidly shredding into fibers. | > 27 |
| 27 | Anthers 1.8-4.5 mm long; ovary apices glabrous | Festuca rubra |
| 27 | Anthers 0.6-1.4 mm long; ovary apices densely pubescent | Festuca earlei |
| 26 | Rhizomes absent; sheaths of the vegetative shoots usually closed for less than 2/3 their length, sometimes closed for about 3/4 their length, usually glabrous and smooth, sometimes scabrous or puberulent, hairs rarely retrorse, senescent sheaths usually persistent for several years, sometimes slowly shredding into fibers. | > 27 |
| 28 | Primary and secondary inflorescence branches stiffly and strongly divaricate at maturity; spikelets with 2(3) florets | Festuca dasyclada |
| 28 | Primary inflorescence branches stiffly erect or laxly spreading at maturity, secondary branches not divaricate; spikelets with (1)2-10 florets. | > 29 |
| 29 | Culms densely scabrous or densely pubescent below the inflorescences; ligules 0.5-1.5(2) mm long; anthers (2)3-4(4.2) mm long | Festuca arizonica |
| 29 | Culms usually smooth and glabrous below the inflorescences, sometimes scabrous or sparsely pubescent, if scabrous or pubescent then the ligules to 0.6 mm long; ligules 0.1-0.8(1) mm long; anthers 0.3-4.5(5) mm long. | > 30 |
| 30 | Lemmas unawned, mucronate, or with awns to 3.5 mm long, if awned then the leaf blades with adaxial sclerenchyma strands present. | > 31 |
| 31 | Blades 0.2-1.2(1.5) mm in diameter; lemmas usually unawned, sometimes mucronate, mucros to 0.4 mm long; ovary apices glabrous or sparsely pubescent; adaxial sclerenchyma absent, pillars and girders not formed; plants introduced, usually of disturbed habitats. | > 32 |
| 32 | Blades with (5)7-9 veins and 5-9 indistinct or distinct ribs; sclerenchyma in (5)7-9 sometimes partly confluent abaxial strands; inflorescences (3)8-18(25) cm long; spikelets (5)6-8.5(10) mm long; lemmas (3.5)4-5.6(6.6) mm long; anthers (2)3-4 mm long | Festuca amethystina |
| 32 | Blades with 5(7) veins and 1 distinct rib; sclerenchyma in a continuous or almost continuous abaxial band; inflorescences 1-6(14) cm long; spikelets 3-6(6.5) mm long; lemmas 2.3-4(4.4) mm long; anthers (1)1.5-2.2 mm long | Festuca filiformis |
| 31 | Blades 0.3-3 mm in diameter; lemmas unawned or with awns to 3.5 mm long; ovary apices pubescent, sometimes sparsely so; usually at least some veins associated with adaxial sclerenchyma and pillars or girders; plants native, of western alpine, subalpine, and montane habitats. | > 32 |
| 33 | Panicle branches erect to stiffly spreading; abaxial sclerenchyma forming continuous or interrupted bands; lower glumes from shorter than to about equal to the adjacent lemmas | Festuca campestris |
| 33 | Panicle branches lax, loosely erect, spreading, recurved, or reflexed; abaxial sclerenchyma in strands about the same width as the adjacent veins, not forming a continuous or interrupted band; lower glumes distinctly shorter than the adjacent lemmas. | > 34 |
| 34 | Senescent sheaths persistent, not shredding into fibers; blades deciduous; spikelets lustrous; ovary apices usually sparsely pubescent, rarely glabrous; plants densely cespitose; plants of alpine or arctic habitats from central British Columbia northward | Festuca altaica |
| 34 | Senescent sheaths persistent or slowly shredding into fibers; blades not deciduous; spikelets not lustrous; ovary apices usually densely pubescent, sometimes sparsely pubescent; plants loosely to densely cespitose; plants of alpine and subalpine habitats from southern British Columbia southward. | > 35 |
| 35 | Blades of the lower cauline leaves shorter and stiffer than those of the upper cauline leaves; lemmas glabrous, smooth or slightly scabrous | Festuca viridula |
| 35 | Blades of the lower cauline leaves similar in length and stiffness to those of the upper cauline leaves; lemmas scabrous or puberulent distally | Festuca washingtonica |
| 30 | Lemmas usually awned, occasionally unawned, awns 0.3-12 mm long; leaf blades without adaxial sclerenchyma strands. | > 31 |
| 36 | Anthers (1.8)2-4.5 mm long; plants mostly not of arctic, subarctic, or alpine habitats (except F. auriculata and F. lenensis) | Subkey I |
| 36 | Anthers 0.3-1.8(2) mm long; plants mostly of arctic, subarctic, or alpine habitats (except F. occidentals, F. ovina, and F. saximontana) | Subkey II |
Festuca Subkey I
| 1 | Ovary apices pubescent. | > 2 |
| 2 | Sheaths closed for about 3/4 their length or more; vegetative shoot leaf blades narrow and conduplicate, the cauline blades broader and flat; anthers 2.5-4.5 mm long | Festuca heterophylla |
| 2 | Sheaths closed for no more than 1/2 their length; vegetative shoot and cauline leaf blades similar, conduplicate; anthers 1-3.5 mm long. 3. Lower inflorescence branches usually reflexed at maturity; lemma awns 3-12 mm long; ovary apices densely pubescent | Festuca occidentalis |
| 3 | Lower inflorescence branches erect at maturity; lemma awns 1-2.5 mm long; ovary apices sparsely pubescent | Festuca calligera |
| 1 | Ovary apices glabrous, or with up to 5 hairs in F. calligera. | > 2 |
| 4 | Abaxial sclerenchyma forming continuous or interrupted bands; lemmas (2.6)3-6(6.2) mm long; blades with 1-3(5) indistinct ribs; anthers 1.4-3 mm long; species used as ornamentals or for turf or soil stabilization, rarely spreading from cultivation. | > 5 |
| 5 | Plants usually not glaucous or pruinose; sheaths glabrous; plants used for turf | Festuca ovina |
| 5 | Plants usually glaucous or pruinose; sheaths pubescent or glabrous; plants grown as ornamentals | Festuca glauca |
| 4 | Abaxial sclerenchyma usually in 3-7 discrete or somewhat confluent strands, if in a continuous band, the lemmas 3.8-7(8.2) mm long; blades with 1-9 distinct ribs; anthers 0.4-4.5 mm long; most species native, a few introduced for turf. | > 5 |
| 6 | Abaxial sclerenchyma in 5-7 strands or in interrupted to continuous bands; blades with (1)3-9 well-defined ribs. | > 7 |
| 7 | Lemmas 3.8-5(6.5) mm long, usually scabrous or pubescent distally, especially on the margins, rarely entirely pubescent; lemma awns usually less than 1/2 the length of the lemma bodies | Festuca trachyphylla |
| 7 | Lemmas 5-10 mm long, scabrous distally; lemma awns usually more than 1/2 the length of the lemma bodies. | > 8 |
| 8 | Blades with (1)3-5 ribs; adaxial surfaces of the blades pubescent or scabrous; inflorescence branches usually somewhat spreading at maturity | Festuca idahoensis |
| 8 | Blades with 5-9 ribs; adaxial surfaces of the blades glabrous or pubescent, sometimes scabrous; inflorescence branches erect to slightly spreading at maturity | Festuca roemeri |
| 6 | Abaxial sclerenchyma strands usually restricted to the margins and midvein, rarely with additional strands in between; blades with 1-5 well-defined ribs. | > 7 |
| 9 | Sheaths closed distinctly less than 1/2 their length; culms 15-65 cm tall; inflorescences 5-15 cm long; plants native to the southwestern United States | Festuca calligera |
| 9 | Sheaths closed for about 1/2 their length; culms 8-50(60) cm tall; inflorescences 1.5-10 cm long; plants introduced or native to the extreme northwest of the Flora region. | > 10 |
| 10 | Inflorescences (3)5-10 cm long, panicles; abaxial blade surfaces glabrous or pubescent, not pilose; lower glumes 2-3 mm long; anthers 2.2-2.6 mm long; plants introduced | Festuca valesiaca |
| 10 | Inflorescences 1.5-5(5.5) cm long, panicles or racemes; abaxial blade surfaces glabrous, pubescent, or pilose, varying within individual plants; lower glumes 2.5-3.4 mm long; anthers (2)2.4-3.5 mm long; plants native to the extreme northwest of the Flora region. | > 11 |
| 11 | Abaxial sclerenchyma strands distinctly narrower than the veins; spikelets 5-6.5(8) mm long | Festuca auriculata |
| 11 | Abaxial sclerenchyma strands about the same width as or wider than the veins; spikelets (5)7-9(11) mm long | Festuca lenensis |
Festuca Subkey II
| 1 | Ovary apices pubescent, sometimes with only a few hairs. 2. Ovary apices densely and conspicuously pubescent. | > 2 |
| 3 | Lemma awns 0.3-1.5 mm long; lemmas 3-4.5 mm long | Festuca earlei |
| 3 | Lemma awns 3-12 mm long; lemmas (4)4.5-6.5(8) mm long | Festuca occidentalis |
| 2 | Ovary apices sparsely and inconspicuously pubescent. | > 3 |
| 4 | Culms densely pubescent or shortly pilose below the inflorescence; lemmas 3.5-6 mm long; anthers 0.3-0.7(1.1) mm long | Festuca baffinensis |
| 4 | Culms glabrous below the inflorescence; lemmas (2)2.2-3.5(4) mm long; anthers (0.4)0.6-1.2 mm long | Festuca minutiflora |
| 1 | Ovary apices glabrous. | > 2 |
| 5 | Abaxial sclerenchyma in a continuous band; anthers longer than 1.4 mm; plants persisting from historical use for turf and soil stabilization | Festuca ovina |
| 5 | Abaxial sclerenchyma in 3+ discrete or confluent strands, rarely in a continuous band; anthers various; plants native in the Flora region. | > 6 |
| 6 | Abaxial sclerenchyma strands at least twice as wide as high, varying to more or less confluent, rarely forming a continuous band; plants of various habitats. | > 7 |
| 7 | Anthers (0.8)1.2-1.7(2) mm long; inflorescences 2-10(13) cm long; lemmas (3)3.4-4(5.6) mm long; spikelets (3)4.5-8.8(10) mm long; plants widespread in continental North America | Festuca saximontana |
| 7 | Anthers 0.8-1.3 mm long; inflorescences 1.5-5 cm long; lemmas (2.5)3-3.5(4) mm long; spikelets 4-5.6(6) mm long; plants known only from Greenland | Festuca groenlandica |
| 6 | Abaxial sclerenchyma strands usually less than twice as wide as high, not confluent, never forming a continuous band; plants restricted to arctic or alpine habitats. | > 7 |
| 8 | Blades usually with 3 abaxial sclerenchyma strands, 2 in the margins and 1 opposite the midvein, occasionally with 2 additional abaxial strands opposite the lateral veins. | > 9 |
| 9 | Abaxial sclerenchyma strands 3(5), narrower than the veins; spikelets 5-6.5(8) mm long | Festuca auriculata |
| 9 | Abaxial sclerenchyma strands 3, about the same width as or wider than the veins; spikelets (5)7-9(11) mm long | Festuca lenensis |
| 8 | Blades with 3-7(9) abaxial sclerenchyma strands. | > 9 |
| 10 | Blades (0.2)0.3-0.4(0.6) mm in diameter; spikelets 2.5-5 mm long, with (1)2-3(5) florets; lemmas (2)2.2-3.5(4) mm long; lemma awns 0.5-1.5(1.7) mm long; plants of alpine habitats | Festuca minutiflora |
| 10 | Blades (0.3)0.4-1.2 mm in diameter; spikelets (3)3.5-8.5 mm long, with 2-6 florets; lemmas 2.5-7 mm long; lemma awns (0.2)0.5-3.5 mm long; plants of arctic or alpine habitats. | > 11 |
| 11 | Culms densely pubescent or pilose below the inflorescences; anthers 0.3-0.7(1.1) mm long | Festuca baffinensis |
| 11 | Culms usually glabrous and smooth below the inflorescences, occasionally slightly scabrous or sparsely puberulent; anthers (0.3)0.4-1.3 mm long. | > 12 |
| 12 | Inflorescences usually panicles; lower branches with 2+ spikelets; flag leaf sheaths not inflated; flag leaf blades (0.3)1-3 cm long | Festuca brachyphylla |
| 12 | Inflorescences often racemes; lower branches with 1-2(3+) spikelets; flag leaf sheaths usually slightly to distinctly inflated; flag leaf blades 0.2-5(8) cm long. | > 13 |
| 13 | Culms erect, more than twice as tall as the basal tuft of leaves; glumes ovate-lanceolate to lanceolate; lemmas (3)4-5.5(7) mm long; plants of Alaska to the western Northwest Territories | Festuca brevissima |
| 13 | Culms erect to prostrate, to twice as tall as the basal tuft of leaves; glumes ovate to ovate-lanceolate; lemmas 2.9-5.2 mm long; plants of Alaska to the eastern arctic. | > 14 |
| 14 | Culms usually erect, sometimes semi-prostrate; flag leaf blades 0.5-5(8) mm long; blades often curved or somewhat falcate; spikelets (3)4-5.5(7) mm long; upper glumes 2.2-3.2 mm long; lemma apices usually minutely bidentate; awns usually slightly subterminal | Festuca hyperborea |
| 14 | Culms usually geniculate to prostrate, becoming erect at anthesis; flag leaf blades (0.3)0.5-2 cm long; most blades straight; spikelets 4.5-8.5 mm long; upper glumes 2.9-4.3 mm long; lemma apices entire; awns usually terminal, sometimes slightly subterminal | Festuca edlundiae |