Click the number at the start of a key lead to highlight both that lead and its corresponding lead. Click again to show only the two highlighted leads. Click a third time to return to the full key with the selected leads still highlighted.
1 Ligule with a dense ring of short hairs 0.5-1 mm long, and behind it a ring of longer hairs 1-5 mm long called the pseudoligule (see introduction for discussion of the so-called double ligule). |
..2 Culms > 100 cm long; node pubescence densely retrorse; larger blades 12-20 cm long; spikelets acute, 1.9-2.3 mm long, 2× or more as long as wide |
..2 Culms < 100 cm long (rarely longer); node pubescence various; larger blades 3-12 cm long; spikelets rounded to blunt, (1.0-) 1.1-2.0 mm long, less than 2 × as long as wide. |
....3 Plants velvety-pubescent throughout; nodes retrorsely bearded; internode pubescence retrorse to spreading; blades usually ciliate above base as well as basally; mature vernal panicles 3-7 cm long, 2-5 cm wide, about 2/3 as wide as long |
....3 Plants densely pubescent to glabrate, but lacking velvety pubescence; nodes with spreading to ascending pubescence (sometimes retrorse in D. villosissimum); internode pubescence ascending, appressed, or spreading; blades ciliate only at base (sometimes appearing ciliate laterally in D. ovale var. ovale); mature vernal panicles 4-10 cm long, nearly or equally as wide. |
......4 Lower internodes with retrorse or spreading hairs to 3+ mm long; blade adaxial surface pilose with hairs to 4+ mm long, these appressed and angled away from the leaf axis; spikelets 2.1-2.5 mm long |
......4 Lower internodes pilose with (spreading-) ascending to appressed hairs, or nearly glabrous; blade adaxial surface sparsely appressed-pubescent to glabrate; spikelets 2.1-3.1 mm long. |
........5 Spikelets 2.1-2.6 mm long; lower culm blades usually sparsely appressed-pubescent on both surfaces, eciliate or ciliate at the base only |
........5 Spikelets 2.5-3.1 mm long; lower culm blades usually glabrous adaxially except for long hairs at or near the margin (appearing ciliate), appressed-pubescent abaxially |
1 Ligule a single structure, without a pseudoligule. |
..........6 Ligule 2-5 mm long, ciliate |
..........6 Ligule < 2 mm long, ciliate or membranous. |
............ 7 Ligule a stramineous to light brown membrane, with or without terminal cilia; peduncle antrorsely scabrous but not hairy. |
............ ..8 Panicle rachis smooth, pellucid-punctate; first glume 0.3-0.6 (-0.8 ) mm long, as broad as or broader than long, truncate to obtuse; larger leaves 10-25 cm long, 8-15 mm wide; ligule 0.5-1.3 mm long; lowest elongate culm internode > 2 mm in diameter; lowest nodes usually glabrous or pubescent |
............ ..8 Panicle rachis scabrous or smooth, not pellucid-punctate; first glume 0.5-1.1 mm long, longer than wide, rounded to acute; larger leaves 3.5-12 cm long, 3-9 mm wide; ligule 0.1-0.6 mm long; lowest elongate culm internode < 2 mm in diameter; lowest nodes retrorsely bearded or glabrous. |
............ ....9 Lowest nodes usually retrorsely bearded; ligules (0.1-) 0.3-0.6 mm long; largest vernal blades 7-12 cm long, (4.5-) 6-9 mm wide; panicle peduncle scabrous; spikelets ovate-lanceolate, acute, 2.0-2.4 mm long; first glume lanceolate, blunt to acute; fertile lemma smooth |
............ ....9 Lowest nodes usually glabrous; ligules 0.1-0.2 (-0.3) mm long; largest vernal blades 3.5-7 cm long, 3-6 mm wide; panicle peduncle smooth; spikelets elliptic, blunt to acute, 1.6-2.2 mm long; first glume ovate to rotund, rounded to acute; fertile lemma papillose |
............ 7 Ligule entirely of white hairs; peduncle variously hairy or glabrous, but not antrorsely scabrous. |
............ ......10 Culms with a viscid band below the retrorsely bearded nodes; internodes, sheaths, and blades velvety-pubescent |
............ ......10 Culms without a viscid band below the retrorsely, spreading, or antrorsely bearded nodes; internodes and sheaths not velvety-pubescent, blades velvety-pubescent in some. |
............ ........11 Basal as well as cauline blades linear, 5-15 cm long,; 1-4 mm wide, 30× or more as long as wide; spikelets 2.8-3.8 (-4.5) mm long |
............ ........11 Blades < 15× as long as wide (if > 15×, then spikelets 1.9-2.5 mm long and sheaths retrorsely pilose in D. laxiflorum). |
............ ..........12 Blades (15-) 20× or more as long as wide, increasing in length upwards on culm; blade adaxial surface (weakly-) strongly scabrous; sheaths glabrous; second glume and sterile lemma exceeding fertile lemma |
............ ..........12 Blades < 15× as long as wide, similar or more often decreasing in size upwards on culm (if increasing, then sheaths strongly retrorsely pilose in D. laxiflorum); blade adaxial surface smooth to moderately scabrous; second glume and sterile lemma shorter than to exceeding fertile lemma. |
............ ............ 13 Nodes retrorsely bearded; larger vernal leaves 7-15 mm wide. |
............ ............ ..14 Sheaths retrorsely pilose with hairs 2-3 mm long; basal leaves usually numerous, ascending, similar in size and shape to the culm leaves; culms branching only at the base in autumnal phase |
............ ............ ..14 Sheaths glabrous or pilose (if pilose, then hairs not both retrorse and 2-3 mm long); basal leaves rosette-forming, usually much shorter than culm leaves; culms branching above base in autumnal phase. |
............ ............ ....15 Plants rarely > 1 m in length; lower internodes glabrous to sparsely hairy; vernal cauline leaves 3-7; spikelets 1.8-2.8 mm long, elliptic to lance-ovate, blunt to acute, glabrous or pubescent |
............ ............ ....15 Plants often > 1 m in length; lowest internodes moderately to densely villous; vernal cauline leaves 6-15; spikelets 1.8-2.2 mm long, obovoid to broadly ellipsoid, rounded to blunt, pubescent |
............ ............ 13 Nodes spreading to antrorsely bearded; larger vernal leaves 3-10 mm wide. |
............ ............ ......16 Culm internodes glabrous to sparsely pilose; culm nodes bearded with long retrorse hairs; blade surfaces glabrous to velvety-pubescent |
............ ............ ......16 Culm internodes, at least the lower, strigose, pilose, or villous; culm nodes bearded with ascending or spreading hairs; blade surfaces glabrous or variously hairy. |
............ ............ ........17 Lower nodes bearded with erect-ascending, soft, and long hairs; mid-culm blades usually 20× or more as long as wide. |
............ ............ ..........18 Spikelets (3.0-) 3.2-3.8 mm long, fusiform, pointed at summit, attenuate at base, with both glumes attached 0.3-0.5 mm below sterile lemma, the autumnal spikelets 3.5-3.8 mm long; larger vernal blades 3-6 mm wide, the lower and mid-culm blades of similar width; autumnal blades involute |
............ ............ ..........18 Spikelets 1.8-3.1 mm long, obovate, blunt, and the base not attenuate except in D. arenicoloides with autumnal spikelets 2.3-3.1 mm long; larger vernal blades 2-8 mm wide, the lower usually wider and often shorter than mid-culm blades; autumnal blades involute or flat. |
............ ............ ............ 19 Longest vernal blades to 16 cm, widest vernal blades 4-8 mm, usually longitudinally wrinkled; vernal and autumnal spikelets 2.3-3.1 mm long; autumnal blades flat, the larger to 9 cm × 2-4 mm |
............ ............ ............ 19 Longest vernal blades to 6 ( D. aciculare) or 12 ( D. arenicoloides) cm long, 2-5 mm wide, not noticeably wrinkled; vernal spikelets 1.5-2.8 mm long, autumnal spikelets either 1.5-2.3 ( D. aciculare) or 2.3-3.1 ( D. arenicoloides); autumnal blades involute, the larger to 6 cm × 1.5 mm. |
............ ............ ............ ..20 Longest vernal blades to 6 (-8) cm, widest vernal blades 2-5 mm; vernal and autumnal spikelets 1.7-2.3 mm long, blunt, not attenuate, the glumes attached <0.2 mm below sterile lemma; first glumes 0.6-0.9 mm long; larger autumnal blades to 3 cm by 1 mm |
............ ............ ............ ..20 Longest vernal blades to 12 cm, widest vernal blades 3-4 (-5) mm; vernal spikelets 2.1-2.8 mm long; autumnal spikelets 2.3-3.1 mm long, pointed, attenuate, the glumes attached 0.3-0.5 mm below sterile lemma; first glumes 0.7-1.5 mm long; larger autumnal blades to 6 cm by 1.5 mm |
............ ............ ........17 Lower and often mid-culm nodes bearded with spreading, stiffish, and short-to-long hairs; mid-culm blades usually 15× or less as long as wide. |
............ ............ ............ ....21 Blades stiff, often longitudinally ribbed, at least the lower villous or strongly pilose on the abaxial surface, and pilose to hirsute on the adaxial surface, at least proximally. |
............ ............ ............ ......22 Spikelets 2.3-3.0 mm long; ligule < 1 mm long; mid-culm blades 4-8 mm wide |
............ ............ ............ ......22 Spikelets 1.7-2.0 (-2.3) mm long; ligule 1-2.5 mm long; mid-culm leaves 2-5 mm wide |
............ ............ ............ ....21 Blades not noticeably stiff nor longitudinally ribbed, pubescent or strigose underneath, glabrous above or with a few long hairs near the base. |
............ ............ ............ ........23 Spikelet bases strongly attenuate, apices blunt to beaked; first glume (2/5-) ½-2/3 (-4/5) as long as spikelet, attached 0.3-0.5 (-0.7) mm belong expansion of second glume and sterile lemma; larger vernal blades 3-6 (-7) mm wide |
............ ............ ............ ........23 Spikelet bases not noticeably attenuate, apices rounded to obtuse; first glume < ½ as long as spikelet, attached < 0.3 mm below expansion of second glume and sterile lemma; larger vernal blades 5-12 mm wide. |
............ ............ ............ ..........24 Culms 50-140 cm long; lowest internodes usually purplish; leaf sheaths often viscid-spotted; leaf blades glabrous abaxially, glabrous and scabrous adaxially; spikelets 1.8-2.2 mm long |
............ ............ ............ ..........24 Culms 15-60 cm long; lowest internodes usually olive- or bluish-green; leaf sheaths not viscid-spotted; leaf blades appressed-pubescent abaxially, glabrous and smooth to appressed pubescent adaxially; spikelets 2.1-3.1 mm long. |
............ ............ ............ ............ 25 Spikelets 2.1-2.6 mm long; lower culm blades usually sparsely appressed-pubescent on both surfaces, eciliate or ciliate at the base only |
............ ............ ............ ............ 25 Spikelets 2.5-3.1 mm long; lower culm blades usually glabrous adaxially except for long hairs at or near the margin (appearing ciliate), appressed-pubescent abaxially |