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1 Both lower and upper glumes absent, or upper glume present on terminal spikelet only of a panicle branch. |
..2 Plants stoloniferous; culms to 40 cm long; blades to 4 mm wide; spikelets 3.8-5.2 mm long, apex acuminate; upper glume sometimes present on terminal spikelet of a panicle branch |
..2 Plants cespitose; culms to 200 cm long; blades to 35 mm wide; spikelets 1.8-2 mm long, apex obtuse; both glumes absent from all spikelets |
1 At least upper glume present on all spikelets. |
....3 Spikelets solitary, not associated with rudimentary spikelets or naked pedicels. |
......4 Panicles usually composed of a terminal pair of branches, sometimes with 1 (-5) additional branches below the terminal pair. |
........5 Upper glumes pubescent on the back or margins. |
..........6 Spikelets 1.3-1.9 mm long; upper glumes pilose along the margins; ligules 0.5-0.8 mm long; panicle branch axis 0.2-0.8 mm wide |
..........6 Spikelets 2.4-3.2 mm long; upper glumes sparsely pubescent on the back; ligules 1-2 mm long; panicle branch axis 1.2-2.2 mm wide |
........5 Upper glumes glabrous. |
............ 7 Spikelets elliptic, the tip acute or acuminate. |
............ ..8 Plants short-rhizomatous, culms appearing cespitose; blades to 4 mm wide; spikelets 3-3.6 mm long; lower lemmas 5-veined; upper florets stramineous to golden brown; most frequently found along roadsides and in pastures |
............ ..8 Plants rhizomatous, the culms separate; blades to 8 mm wide; spikelets 3-4.5 mm long; lower lemmas 3-veined; upper florets white; most frequently found in brackish and salt marshes |
............ 7 Spikelets ovate to broadly elliptic, the tip obtuse to broadly acute. |
............ ....9 Culms to 60 cm long; blades flat; panicle branches to 6.4 cm long; spikelets 1.9-2.3 mm long, 1.2-2 mm wide; upper glumes 3-veined |
............ ....9 Culms to 120 cm long; blades flat or longitudinally folded; panicle branches to 15 cm long; spikelets 2.5-4 mm long, 2-2.8 mm wide; upper glumes 5-veined |
......4 Panicles with 1-70 branches; if > 1, the branches arranged racemosely, the 2 uppermost not paired. |
............ ......10 Panicle branches 7-70, the axes extending beyond the outermost spikelets; panicle branches disarticulating at maturity |
............ ......10 Panicle branches 1-6, terminating in a spikelet; panicle branches persistent. |
............ ........11 Upper florets olive to dark brown |
............ ........11 Upper florets pale to tan. |
............ ..........12 Axes of panicle branches not broadly winged, 0.6-1.3 mm wide. |
............ ............ 13 Spikelets orbicular, 2.8-3.2 mm wide |
............ ............ 13 Spikelets slightly longer than broad, 2.0-2.5 mm wide |
............ ..........12 Axes of panicle branches broadly winged, 1.8-3.3 mm wide. |
............ ............ ..14 Culms to 100 cm long; spikelets 3.2-4 mm long, 1.6-1.7 mm wide; upper lemmas with a few short hairs at their tips; caryopses 2-3 mm long |
............ ............ ..14 Culms to 50 cm long; spikelets 1.7-2.1 mm long 1.1-1.4 mm wide; upper lemmas glabrous; caryopses 1-1.3 mm long |
....3 Spikelets paired, or at least the second nonfunctional spikelet represented by a naked pedicel. |
............ ............ ....15 Spikelets 1.0-1.3 mm long |
............ ............ ......16 Nodes glabrous; blades 1.9-8 mm wide; panicle branches 2-6; upper florets 0.8-1.1 mm long |
............ ............ ......16 Nodes pubescent; blades 10-24 mm wide; panicle branches 18-50; upper florets 1.1-1.3 mm long |
............ ............ ....15 Spikelets 1.3-4.1 mm long. |
............ ............ ........17 Margins of upper glumes and lower lemmas fimbriate, or ciliate with soft hairs 5 mm or more long. |
............ ............ ..........18 Culms to 70 cm long; upper glumes and lower lemmas broadly winged, the wing fimbriate; spikelets 2.4-3 mm wide |
............ ............ ..........18 Culms to 220 cm long; margins of upper glume and lower lemmas long-ciliate, wingless; spikelets 1.1-2.5 mm wide. |
............ ............ ............ 19 Panicle branches 2-7; spikelets 2.3-4.0 mm long, 1.7-2.5 mm wide |
............ ............ ............ 19 Panicle branches (4-) 10-30; spikelets 1.8-2.8 mm long, 1.1-1.5 mm wide |
............ ............ ........17 Margins of upper glumes and lower lemmas glabrous or pubescent, but not winged, fimbriate, or long-ciliate. |
............ ............ ............ ..20 Upper florets olive to dark brown. |
............ ............ ............ ....21 Plants aquatic AND culms decumbent; lower glumes often present |
............ ............ ............ ....21 Plants either not aquatic OR if aquatic then with erect culms; lower glumes absent. |
............ ............ ............ ......22 Panicle branches 10-28 (occasionally more). |
............ ............ ............ ........23 Plants annual; axes of panicle branches broadly winged, the wings about as wide as the central portion; [common native] |
............ ............ ............ ........23 Plants perennial; axes of panicle branches narrowly winged, the wings narrower than the central portion; [rare exotics]. |
............ ............ ............ ..........24 Blades 7-18 mm wide; axes of panicle branches 0.5-1.2 mm wide; spikelets 1.1-1.8 mm wide; upper florets 1.8-2.2 mm long |
............ ............ ............ ..........24 Blades 10-30 mm wide; axes of panicle branches 1-1.7 mm wide; spikelets 1.8-2.4 mm wide; upper florets 2.5-2.7 mm long |
............ ............ ............ ......22 Panicle branches 1-10. |
............ ............ ............ ............ 25 Upper glumes glabrous. |
............ ............ ............ ............ ..26 Blades to 15 mm wide; panicle branches 1-10 (-28); branch axes 0.7-2.3 mm wide; spikelets 2-2.2 mm long |
............ ............ ............ ............ ..26 Blades to 7 mm wide; panicle branches 2-8; branch axes 0.6-1.1 mm wide; spikelets 2.2-3 mm long. |
............ ............ ............ ............ ....27 Panicle branches 2-7, 1.6-7.1 cm long; spikelets 2.5-3 mm long, 1.5-2.2 mm wide; upper florets dark brown |
............ ............ ............ ............ ....27 Panicle branches 5-8, 3.5-11 cm long; spikelets 2.2-2.7 mm long, 1-1.4 mm wide; upper florets chestnut brown |
............ ............ ............ ............ 25 Upper glumes pubescent. |
............ ............ ............ ............ ......28 Rhizomes 5-25 cm long; ligule 1.2-1.5 mm long; panicle branches to 5.2 cm long; mature lower lemma transversely rugose |
............ ............ ............ ............ ......28 Rhizomes indistinct or absent; ligule 1-4.1 mm long; panicle branches to 11 cm long; mature lower lemma not transversely rugose. |
............ ............ ............ ............ ........29 Ligules 1-2 mm long; panicle branches 4-13, 6-11 cm long; spikelets 1.1-1.8 mm wide |
............ ............ ............ ............ ........29 Ligules 2-4.1 mm long; panicle branches 1-7, 1.1-7.1 cm long; spikelets 1.5-2.4 mm wide. |
............ ............ ............ ............ ..........30 Plants annual; culms to 53 cm long; blades to 12 mm wide, flat; ligules 2-4.1 mm long; branch axes 0.8-1.3 mm wide; spikelets 2.1-2.6 mm long |
............ ............ ............ ............ ..........30 Plants perennial; culms to 110 cm long; blades to 5.4 mm wide, usually conduplicate; ligules 2-3 mm long; branch axes 0.6-1.1 mm wide; spikelets 2.5-3 mm long |
............ ............ ............ ..20 Upper florets white, stramineous, or golden brown. |
............ ............ ............ ............ ............ 31 Panicle with 15-100 branches. |
............ ............ ............ ............ ............ ..32 Plants annual; ligules 0.1-0.3 mm long; blades to 13 cm long; panicle branches to 2.5 cm long; upper glumes and lower lemmas rugose |
............ ............ ............ ............ ............ ..32 Plants perennial; ligules 1-6.3 mm long; blades to 62 cm long; panicle branches to 13 cm long; upper glumes and lower lemmas smooth. |
............ ............ ............ ............ ............ ....33 Plants rhizomatous; nodes and sheaths glabrous; panicle branch axes 0.9-1.2 mm wide |
............ ............ ............ ............ ............ ....33 Plants cespitose; nodes and sheaths pubescent; panicle branch axes 0.3-0.6 mm wide. |
............ ............ ............ ............ ............ ......34 Culms to 400 cm long; blades 10-23 mm wide; panicle branches 5-13 cm long, spreading to reflexed; spikelets 1.8-1.9 mm wide |
............ ............ ............ ............ ............ ......34 Culms to 180 cm long; blades 4.9-6.1 mm wide; panicle branches 1.2-8.5 cm long, erect to ascending; spikelets 0.9-1.3 mm wide |
............ ............ ............ ............ ............ 31 Panicles with 1-15 branches. |
............ ............ ............ ............ ............ ........35 Spikelets 1.3-2.5 mm long. |
............ ............ ............ ............ ............ ..........36 Upper glumes and often lower lemmas shortly pubescent. |
............ ............ ............ ............ ............ ............ 37 Lower glumes present |
............ ............ ............ ............ ............ ............ 37 Lower glumes absent. |
............ ............ ............ ............ ............ ............ ..38 Panicles both terminal and axillary, the axillary panicles partially or completely enclosed by the subtending leaf sheath |
............ ............ ............ ............ ............ ............ ..38 Panicles all terminal |
............ ............ ............ ............ ............ ..........36 Upper glumes and lower lemmas glabrous. |
............ ............ ............ ............ ............ ............ ....39 Panicles both terminal and axillary, the axillary panicles partially or completely enclosed by the subtending leaf sheath |
............ ............ ............ ............ ............ ............ ....39 Panicles all terminal. |
............ ............ ............ ............ ............ ............ ......40 Ligules 0.2-0.4 mm long; branch axes 0.2-0.5 mm wide; spikelets 1.3-2 mm long, 0.7-1 mm wide |
............ ............ ............ ............ ............ ............ ......40 Ligules 0.5-4.7 mm long; branch axes 0.3-2 mm wide; spikelets 1.6-3.1 mm long, 1-2.8 mm wide. |
............ ............ ............ ............ ............ ............ ........41 Ligules 2.2-4.7 mm long; branch axes 1.5-2 mm wide, broadly winged |
............ ............ ............ ............ ............ ............ ........41 Ligules 0.5-2.9 mm long; branch axes 0.4-2 mm wide, narrowly winged or wingless. |
............ ............ ............ ............ ............ ............ ..........42 Spikelets 2-2.8 mm wide, orbicular to suborbicular. |
............ ............ ............ ............ ............ ............ ............ 43 Lower sheaths villous or hirsute; spikelets 2.6-3.5 mm long |
............ ............ ............ ............ ............ ............ ............ 43 Lower sheaths glabrous or sparsely papillose-pubescent; spikelets 2.2-2.8 mm long |
............ ............ ............ ............ ............ ............ ..........42 Spikelets 1-1.9 mm wide, elliptic, ovate, or obovate. |
............ ............ ............ ............ ............ ............ ............ ..44 Spikelets 1.6-2.2 mm long, 1.1-1.3 mm wide |
............ ............ ............ ............ ............ ............ ............ ..44 Spikelets 2.1-3.7 mm long, 1-1.9 mm wide. |
............ ............ ............ ............ ............ ............ ............ ....45 Blades 0.2-2 (rarely -8) mm wide; panicle branch axes 0.5-1.2 mm wide; spikelets 2.3-3.7 mm long, 1.3-1.9 mm wide |
............ ............ ............ ............ ............ ............ ............ ....45 Blades 3-7 mm wide; panicle branch axes 0.3-0.8 mm wide; spikelets 2.2-2.5 mm long, 1-1.3 mm wide |
............ ............ ............ ............ ............ ........35 Spikelets 2.5-4.1 mm long. |
............ ............ ............ ............ ............ ............ ............ ......46 Spikelet pairs hardly imbricate, irregularly approximate, with evident gaps between groups of spikelets on the branches; lower glumes usually present; upper glumes (6-) 7-veined |
............ ............ ............ ............ ............ ............ ............ ......46 Spikelet pairs imbricate; lower glumes absent or present; upper glumes 1-5-veined. |
............ ............ ............ ............ ............ ............ ............ ........47 Upper glumes and lower lemmas pubescent (sparsely so, if at all, in P. pubiflorum). |
............ ............ ............ ............ ............ ............ ............ ..........48 Panicle branches 1-4; branch axes 0.2-1 mm wide; spikelets 1.3-1.6 mm wide; lower glumes present |
............ ............ ............ ............ ............ ............ ............ ..........48 Panicle branches 4-9; branch axes 1.1-2.3 mm wide; spikelets 1.5-2 mm wide; lower glumes absent. |
............ ............ ............ ............ ............ ............ ............ ............ 49 Blades 2-5 mm wide; branches ascending to erect; branch axes 1.2-1.5 mm wide; spikelets 2.8-3 mm long, 1.5-1.6 mm wide |
............ ............ ............ ............ ............ ............ ............ ............ 49 Blades 4-18 mm wide; branches ascending to spreading; branch axes 1.1-2.3 mm wide; spikelets 2.8-3.6 mm long, 1.5-2 mm wide. |
............ ............ ............ ............ ............ ............ ............ ............ ..50 Blades becoming narrow basally; spikelets glabrous |
............ ............ ............ ............ ............ ............ ............ ............ ..50 Blades rounded basally; spikelets pubescent |
............ ............ ............ ............ ............ ............ ............ ........47 Upper glumes and lower lemmas glabrous (sometimes sparsely pubescent in P. pubiflorum). |
............ ............ ............ ............ ............ ............ ............ ............ ....51 Plants decumbent or cespitose, non-rhizomatous. |
............ ............ ............ ............ ............ ............ ............ ............ ......52 Plants aquatic; blades to 10 mm wide; panicle branches ascending to erect, to 12 cm long; spikelets 2.5-3 mm long, 1.3-1.6 mm wide; lower glumes often present; upper glumes and lower lemmas with 5 veins |
............ ............ ............ ............ ............ ............ ............ ............ ......52 Plants terrestrial; blades to 18 mm wide; panicle branches ascending to spreading, to 7.9 cm long; spikelets 2.8-3.6 mm long, 1.5-2 mm wide; lower glumes absent; upper glumes and lower lemmas with 3 veins. |
............ ............ ............ ............ ............ ............ ............ ............ ........53 Blades narrowing basally; spikelets glabrous |
............ ............ ............ ............ ............ ............ ............ ............ ........53 Blades rounded basally; spikelets pubescent |
............ ............ ............ ............ ............ ............ ............ ............ ....51 Plants rhizomatous (shortly so in Paspalum praecox). |
............ ............ ............ ............ ............ ............ ............ ............ ..........54 Blades 0.2-2 (-8) mm wide, involute; panicle branches 1-3; upper glumes 1-veined |
............ ............ ............ ............ ............ ............ ............ ............ ..........54 Blades 2.2-18 mm wide, flat to folded; panicle branches 1-10; upper glumes 3-5-veined. |
............ ............ ............ ............ ............ ............ ............ ............ ............ 55 Ligules to 3.3 mm long; blades to 18 mm wide; spikelets 2.9-4.1 mm long; upper glumes 5-veined; upper florets golden brown |
............ ............ ............ ............ ............ ............ ............ ............ ............ 55 Ligules to 2.2 mm long; blades to 8.3 mm wide; spikelets 2.1-3.1 mm long; upper glumes 3-veined; upper florets white, straminous, light yellow or golden brown. |
............ ............ ............ ............ ............ ............ ............ ............ ............ ..56 Blades 3-4 mm wide, flat; panicle branches 1-3, erect, 7-15 cm long; spikelets 2.7-3 mm long, 1.4-2 mm wide |
............ ............ ............ ............ ............ ............ ............ ............ ............ ..56 Blades 2.2-8.3 mm wide, folded to flat; panicle branches 2-10, ascending to spreading, 0.8-10.3 cm long; spikelets 2.1-3.1 mm long, 2-2.8 mm wide. |
............ ............ ............ ............ ............ ............ ............ ............ ............ ....57 Lower sheaths villous or hirsute; spikelets 2.6-3.5 mm long |
............ ............ ............ ............ ............ ............ ............ ............ ............ ....57 Lower sheaths glabrous or sparsely papillose-pubescent; spikelets 2.2-2.8 mm long |
1 Inflorescences spikelike branches, the spikelets partially embedded in the rachises |
1 Inflorescences panicles or spikes (if spikes, the spikelets not embedded. |
..2 Spikelets (at least the terminal) subtended by 1-many stiff, terete bristles. |
....3 Bristles persistent on the inflorescence, each spikelet disarticulating above the bristles |
....3 Bristles falling with the spikelets at maturity (the disarticulation at the base of the fascicles) |
..2 Spikelets not subtended by stiff bristles. |
......4 Inflorescences of spikelike branches 1-3.7 cm long, the branch extending 2.5-4 mm beyond the attachment of the distal spikelets |
......4 Inflorescences not as above. |
........5 Upper florets laterally compressed |
........5 Upper florets dorsally compressed. |
..........6 Lower glumes or lower lemmas awned. |
............ 7 Leaves > 10× as long as wide; ligules absent or of hairs |
............ 7 Leaves < 8× as long as wide; ligules present, membranous or of hairs. |
............ ..8 Lower glumes unawned or very shortly so; upper glumes ciliate-margined; plants erect or basally decumbent |
............ ..8 Lower glumes awned; upper glumes not ciliate-margined; culms trailing; plants strongly trailing, rooting at the nodes |
..........6 Lower glumes and lower lemmas unawned. |
............ ....9 Lemma margins flat, hyaline; lower glumes absent or < ¼ the length of the upper glume. |
............ ......10 Subterranean (cleistogamous) inflorescences present; aerial inflorescences with elongate rachises; spikelets of the aerial inflorescences often sterile; spikelets glabrous; leaves either with a white cartilaginous margin or prominently ciliate; [of the Coastal Plain] |
............ ......10 Subterranean inflorescences absent; aerial inflorescences either with digitate or subdigitate branches and glabrous spikelets, or with elongate rachises and conspicuously pubescent spikelets; spikelets of the aerial inflorescences fertile; spikelets glabrous, ciliate, or pubescent; leaves various (often not as above); [collectively widespread] |
............ ........11 Inflorescence a narrow panicle with the branches strongly ascending to appressed; spikelets ellipsoid to obovoid; [of Coastal Plain pinelands] |
............ ........11 Inflorescence either a panicle with digitate or subdigitate clusters of spikelike branches or a broad panicle with widely divergent branches; [widespread] |
............ ....9 Lemma margins not hyaline, frequently involute; lower glumes various (absent, < ¼ the length, to longer than the upper glume). |
............ ..........12 Spikelets subtended by a cuplike callus |
............ ..........12 Spikelets not subtended by a cuplike callus. |
............ ............ 13 Leaves primarily lacking ligules (at least the upper, and often all, leaves without ligules, if vestigial ligules present, these of hairs) |
............ ............ 13 Leaves with ligules, these either membranous or of hairs. |
............ ............ ..14 Lower (sterile) palea indurate and expanding the spikelet at maturity, as long as the lower (sterile) lemma; lower and upper florets standing apart from one another at maturity; outer surface of the upper (fertile) palea with compound papillae |
............ ............ ..14 Lower (sterile) palea membranous, not expanding the spikelet at maturity, usually shorter than lower (sterile) lemma, or absent; lower and upper florets closely appressed at maturity; outer surface of the upper (fertile) palea lacking compound papillae. |
............ ............ ....15 Inflorescence of 1-sided, spikelike primary branches. |
............ ............ ......16 Spikelets with lower lemmas (and lower glumes, if present) adjacent to the branch axes. |
............ ............ ........17 Lower glumes absent |
............ ............ ........17 Lower glumes present on at least most spikelets |
............ ............ ......16 Spikelets with upper lemmas (and upper glumes, if present) adjacent or appressed to the branch axes. |
............ ............ ..........18 Both glumes absent from all or most spikelets |
............ ............ ..........18 Upper or both glumes present on all spikelets. |
............ ............ ............ 19 Lower glumes usually absent; upper lemmas smooth to slightly rugose |
............ ............ ............ 19 Lower glumes present; upper lemmas rugose and verrucose |
............ ............ ....15 Inflorescence either paniculate with well-developed secondary branchlets or if the primary branches spikelike, then the spikelets not borne in a 1-sided arrangement on the spicate branches. |
............ ............ ............ ..20 Inflorescences dense, the spikelets obscuring most of the internal branches |
............ ............ ............ ..20 Inflorescences open panicles, or if narrowed, all or nearly all the panicle branches readily visible. |
............ ............ ............ ....21 First glume 5-7.5 mm long, nearly as long as sterile lemma; fertile lemma 1/3 length of sterile lemma; rachilla prolonged between the florets |
............ ............ ............ ....21 First glume shorter, or if this long, then at most 3/4 length of sterile lemma; fertile lemma > ½ the length of the sterile lemma; rachilla not prolonged between the florets. |
............ ............ ............ ......22 Plant developing a terminal (“spring”) inflorescence usually before mid-summer, followed by lateral (“autumnal”) inflorescences from lower, mid, and/or upper nodes, these often included or hidden among the fascicles of smaller “autumnal” leaves; often developing a rosette of overwintering basal leaves |
............ ............ ............ ......22 Plant developing a terminal inflorescence usually after mid-summer, the lateral inflorescences, when present, from the upper nodes, usually appearing at the same time as the terminal panicle, and not hidden by dense fascicles of smaller leaves; plants lacking a rosette of overwintering basal leaves. |
............ ............ ............ ........23 Spikelets tuberculate (or tuberculate-hispid) |
............ ............ ............ ........23 Spikelets smooth, not tuberculate. |
............ ............ ............ ..........24 Panicle < 2 cm wide at maturity. |
............ ............ ............ ............ 25 Spikelets > 4.5 mm long; first glume > 2.4 mm long; ligule 4-6 mm long; [of coastal dunes] |
............ ............ ............ ............ 25 Spikelets < 4 mm long; first glume < 2.1 mm long; ligule < 2 mm long; [not of coastal dunes]. |
............ ............ ............ ............ ..26 Blades involute, 1.5-4 mm wide; culms wiry |
............ ............ ............ ............ ..26 Blades flat, the larger 6-20 mm wide; culms stout. |
............ ............ ............ ............ ....27 Panicles constricted, 0.3-1.6 cm wide; spikelets subsessile to short-pediceled; summit of fertile palea not enclosed by fertile lemma |
............ ............ ............ ............ ....27 Panicles > 1 cm wide; spikelets short to long-pedicelled; summit of fertile palea enclosed by fertile lemma |
............ ............ ............ ..........24 Panicle > 2 cm wide at maturity. |
............ ............ ............ ............ ......28 Fertile lemmas rugose with cross-venation between the main parallel veins |
............ ............ ............ ............ ......28 Fertile lemmas not rugose. |
............ ............ ............ ............ ........29 Lower primary panicle branches in whorls of 4-7 at the nodes, stiffly spreading, naked on the proximal ½, the axils strongly pilose; lower culm internodes appressed papillose-pubescent; first glume acuminate, ½ as long as spikelet; fertile lemma chestnut brown at maturity |
............ ............ ............ ............ ........29 Plants without the above combination of characters. |
............ ............ ............ ............ ..........30 Plants from a cluster of fibrous roots, without rhizomes or hard knotty crowns, annual |
............ ............ ............ ............ ..........30 Plants with rhizomes or hard knotty crowns, perennial. |
............ ............ ............ ............ ............ 31 Plants with hard crowns, lacking rhizomes; fertile lemma 1.2-1.6 mm long |
............ ............ ............ ............ ............ 31 Plants with rhizomes; fertile lemma 1.6-4 mm long. |
............ ............ ............ ............ ............ ..32 Rhizomes about 1 cm thick with pubescent scale-like leaves; lower portion of culm hard, nearly woody |
............ ............ ............ ............ ............ ..32 Rhizomes less than 1 cm thick with glabrous scale-like leaves; culms not woody. |
............ ............ ............ ............ ............ ....33 First glume truncate apically |
............ ............ ............ ............ ............ ....33 First glume acute to obtuse. |
............ ............ ............ ............ ............ ......34 Culms slightly compressed below; ligules 0.5 mm long or less; spikelet pedicels appressed, the spikelets subsecund, usually some obliquely bent above the first glume; fertile lemma 1.8-2.2 mm long |
............ ............ ............ ............ ............ ......34 Culms terete; ligules 1-6 mm long; at least some spikelet pedicels spreading, spikelets not at all secund, essentially straight; fertile lemma 2-4 mm long |
1 Spikelets 2-flowered, often dorsally compressed, falling entire at maturity (the abscission below the glumes), the upper floret usually bisexual, the lower one male or sterile; [tribe Paniceae] |
..2 Lemma margins hyaline, flat; lower glumes various (absent, < ¼ the length, or longer than the upper glume) |
..2 Lemma margins not hyaline, frequently involute; lower glumes absent or < ¼ the length of the upper glume. |
....3 Spikelets with lower lemmas (and lower glumes, if present) adjacent to the branch axes. |
......4 Lower glumes absent |
......4 Lower glumes present on at least most spikelets |
....3 Spikelets with upper lemmas (and upper glumes, if present) adjacent or appressed to the branch axes. |
........5 Both glumes absent from all or most spikelets |
........5 Upper or both glumes present on all spikelets. |
..........6 Lower glumes usually absent; upper lemmas smooth to slightly rugose |
..........6 Lower glumes present; upper lemmas rugose and verrucose |
1 Spikelets 1-, 2-, or many-flowered, usually terete or somewhat laterally compressed, either abscising at maturing above the glumes or if 2-flowered then both florets bisexual, or the upper sterile; [tribes Cynodonteae and Zoysieae] |
............ 7 Spikes normally solitary (rarely 2), divergent at the summit of the culm; second glume with a recurved spine arising from the back; fresh plants aromatic with a citrus odor; [tribe Cynodonteae; subtribe “incertae sedis”] |
............ 7 Spikes normally 2 or more, alternate, digitate, subdigitate, or verticillate along the main inflorescence axis; second glume lacking a recurved spine; fresh plants not aromatic with a citrus odor. |
............ ..8 Spikes arranged along the central inflorescence axis alternately, solitary at each node. |
............ ....9 Spikelets with 1 bisexual floret, sometimes also with modified male, sterile, or rudimentary florets above the fertile floret. |
............ ......10 Spikelets with modified male, sterile, or rudimentary florets above the fertile floret; [plants of uplands]; [tribe Cynodonteae; subtribe Boutelouinae] |
............ ......10 Spikelets lacking any modified florets; [plants of wetlands, primarily saline and coastal]; [tribe Zoysieae; subtribe Sporobolinae] |
............ ....9 Spikelets with 2 or more bisexual florets (sometimes also with additional reduced florets); [tribe Cynodonteae; subtribe Eleusininae]. |
............ ........11 Ligules 4-8 (-15) mm long, acute to attenuate, entire (lacerate only by tearing) |
............ ........11 Ligules 0.3-5.4 mm long, truncate to obtuse, erose or entire. |
............ ..........12 Lemmas 3-veined; ligule (0.2-) 0.5-5.5 (-7.0) mm long; apex erose or entire |
............ ..........12 Lemmas 5-veined; ligule 0.8-2.2 mm long, apex erose |
............ ..8 Spikes arranged along the central inflorescence axis in a digitate, subdigitate, or verticillate manner, all or most nodes with 2 or more spikes; [tribe Cynodonteae]. |
............ ............ 13 Spikelets with 1 fertile floret (there may also be 1 or more sterile florets); [tribe Cynodonteae; subtribe Eleusininae]. |
............ ............ ..14 Spikelets lacking sterile florets |
............ ............ ..14 Spikelets with 1 or more sterile florets. |
............ ............ ....15 Lowest lemmas awned (rarely unawned); upper glumes acute to acuminate, mucronate or short-awned |
............ ............ ....15 Lowest lemmas unawned (or with an awn to 1.2 mm long); upper glumes truncate or bilobed, sometimes short-awned from between the lobes |
............ ............ 13 Spikelets with 2 or more fertile florets. |
............ ............ ......16 Spikes to 7 cm long, terminating in a point (the spikes acuminate); [tribe Cynodonteae; subtribe “incertae sedis”] |
............ ............ ......16 Spikes to 22 cm long, terminating in a functional or rudimentary spikelet (the spikes acute to obtuse); [tribe Cynodonteae; subtribe Eleusininae]. |
............ ............ ........17 Lemmas glabrous |
............ ............ ........17 Lemmas pubescent, at least towards the base. |
............ ............ ..........18 Lemma apices obtuse to truncate or emarginate |
............ ............ ..........18 Lemma apices acute |