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1 Nodes (at least the lower) densely bearded with retrorse hairs; spikelets 3.3-5.2 mm long; ligule ciliate, the membranous base minute or obsolete. |
2 Ligule 2.5-4 mm long; lower internodes pubescent with long ascending or spreading hairs; cauline blades 8-15 cm long, 10-25 mm wide; first glume 1.8-2.5 mm long |
2 Ligule 0.3-1.3 mm long; lower internodes glabrous or pubescent with ascending hairs; cauline blades 5-15 cm long, either 1-13 or 12-40 mm wide; first glume 1.2-2.2 mm long. |
3 Basal as well as cauline blades linear, 1-4 mm wide, > 30× as long as wide; spikelets 2.8-3.8 (-4.5) mm long |
3 Cauline blades narrowly lanceolate to broadly ovate- lanceolate, 4-40 mm wide, < 20× as long as wide; spikelets 3.3-5.2 mm long. |
4 Blades 12-40 mm wide, broadly ovate- lanceolate, basally cordate; spikelets 3.8-5.2 mm long, 1.7-2.2 mm wide; first glume narrowly triangular; second glume shorter than fertile lemma |
4 Blades 4-14 mm wide, narrowly lanceolate to lanceolate, basally narrowed, rounded, or subcordate; spikelets 3.3-4.5 mm long, 1.2-1.9 mm wide; first glume broadly ovate to triangular; second glume 0.0-0.5 mm longer than fertile lemma. |
5 Lowest elongate internode puberulent to glabrous; lower culm sheaths shorter than internodes, upper culm sheaths longer; blades lanceolate, about 10× as long as wide; blade bases narrowly rounded to subcordate; spikelets 3.3-4.0 mm long, blunt to acute; first glume broadly ovate; second glume equaling or exceeding fertile lemma by 0.2 mm |
5 Lowest elongate internode moderately to densely papillose- pubescent with spreading to ascending hairs; all culm sheaths shorter than internodes; blades narrowly lanceolate, about 15× as long as wide; blade bases narrowed; spikelets 3.5-4.5 mm long, beaked; first glume triangular to ovate; second glume exceeding fertile lemma by 0.2-0.5 mm |
1 Nodes glabrous, pubescent, or sparsely pilose; spikelets (2.4-) 3.3-4.2 mm long; ligules membranous, ciliate, or both. |
6 Ligule 1.6-3 mm long; blades 4-9 mm wide, > 10× as long as wide |
6 Ligule 0.2-1.5 mm long; if larger blades < 9 mm wide and mostly 15× or more as long, then ligule 0.5-1 mm long. |
7 Larger blades 2-6 (-8) mm wide, 10-15× or more as long as wide (if shorter, then culms arising from hard corm-like bases and culms with 8-14 leaves); spikelets basally attenuate. |
8 Culm bases not corm-like; blades usually 15× or more as long as wide, their bases narrowed; vernal panicle usually matures before development of primary branches; upper glume and sterile lemma exceeding fertile lemma, beak-like |
8 Culm bases hard, corm-like; blades usually 10-15× as long as wide, their bases rounded to truncate; primary branches usually develop before maturation of vernal panicle; upper glume about 0.3 mm shorter than fertile lemma, sterile lemma about equaling fertile lemma. |
9 Cauline leaves 8-14; blades thick, puberulent, parallel-sided proximally; ligule of cilia only; vernal panicles 3-13 × 2-8 cm; pedicels ± appressed; lower glumes deltoid, bases fully encircling pedicel |
9 Cauline leaves 4-7; blades thin, glabrous to sparsely hirsute, widening proximally; ligule a ciliate membrane; vernal panicles 3-6 × 2-4 cm; pedicels ± divergent; lower glumes narrowly triangular, bases partially encircling pedicel |
7 Larger blades 6-35 mm wide, mostly 10× or less as long as wide; spikelet bases rounded to narrowed. |
10 Spikelets strongly papillose- hispid with spreading hairs 0.5-1 mm long; blades papillose- hispid |
10 Spikelets glabrous to pubescent with hairs < 0.5 mm long; blades glabrous, scabrous, or pubescent. |
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11 Spikelet apex rounded to sub- acute; second glume and sterile lemma equaling or shorter than fertile lemma. |
12 Ligules 1-1.5 mm long; blades 5-10 cm long by 6-15 mm wide, glabrous or pubescent, basally rounded; spikelets glabrous to pubescent |
12 Ligules 0.3-1 mm long; blades 7-35 cm long by 8-35 mm wide, glabrous or scabrous, basally cordate or rounded; spikelets pubescent to glabrate. |
13 Sheaths (at least lower) papillose- hispid with spreading hairs; ligule 0.5-1.2 mm long, an eciliate membrane; culm blades 10-28 cm long; spikelets 2.4-3.6 mm long; first glume 1.2-1.8 mm long |
13 Sheaths glabrous or pubescent (the upper papillose- pubescent in D. xanthophysum); ligules 0-0.7 mm long, ciliate if more than 0.3 mm long; culm blades 5-18 cm long; spikelets 2.2-4.1 mm long; first glume 0.7-2.6 mm long. |
14 Upper sheaths glabrous to softly villous basally; ligules 0.4-0.7 mm long, a short- ciliate membrane; culm blades 15-40 mm wide, the bases cordate- clasping; panicle usually more than half as wide as long |
14 Upper sheaths glabrous, puberulent, or papillose- pubescent; ligules 0-0.5 mm long, eciliate or ciliate; culm blades 5-25 mm wide, the bases cordate- clasping or rounded; panicles less or more than half as wide as long. |
15 Upper sheaths glabrous or puberulent; ligules 0-0.3 mm long, eciliate; culm blades cordate- clasping; panicles usually more than half as wide as long; spikelets 3.3-3.7 mm long, ellipsoid, apex obtuse to pointed |
15 Upper sheaths papillose- pubescent; ligules 0.3-0.5 mm long, ciliate; culm blade bases rounded; panicles usually less than half as wide as long; spikelets 3.2-4.1 mm long, obovoid, blunt |
1 Culm nodes, at least the lower, bearded (often retrorsely). |
2 Nodes with a viscid band below the beard; internodes and sheaths velvety- pubescent; vernal culm blades 9-20 cm long, 9-20 mm wide |
2 Nodes without a viscid band below the beard; internodes and sheaths glabrous, the lower sometimes sparsely hairy; vernal culm blades 3.5-14 cm long, 7-15 mm wide |
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3 Second glume and sterile lemma acute to short- acuminate, some in a given specimen 0.3 mm or more longer than fertile lemma. |
4 Ligule an eciliate membrane; peduncle scabrous; first glume 0.3-0.6 (-0.8) mm long, reniform to suborbicular |
4 Ligule a ciliate membrane or entirely ciliate; peduncle smooth; first glume 0.7-1.6 mm long, broadly ovate to lanceolate. |
5 Ligule a ciliate membrane; larger leaves 10-20 cm long; spikelets pubescent, (2.6-) 2.8-3.4 (-3.6) mm long; first glume (0.9-) 1.0-1.6 mm long |
5 Ligule entirely ciliate; larger leaves 9-14 cm long; spikelets glabrous, 2.1-2.6 mm long; first glume 0.7-1.2 mm long |
3 Second glume and sterile lemma blunt to subacute, shorter than, equaling, or barely exceeding fertile lemma, never by as much as 0.3 mm. |
6 Ligule ciliate, 0.2-1.1 (-2.1) mm long; leaf blades 5-14 cm by 5-17 mm; second glume 0-0.3 mm shorter than fertile lemma. |
7 Culms 30-75 cm long; lower sheaths glabrous to sparsely papillose- pilose; panicle pulvini glabrous to sparsely pilose; spikelets 1.8-2.6 mm long; first glume narrowly triangular ( triangular- ovate); second glume 0-0.1 mm shorter than fertile lemma |
7 Culms 60-150 cm long; lower sheaths papillose- pilose; panicle pulvini pubescent; spikelets 2.2-2.8 (-3.0) mm long; first glume broadly ovate; second glume 0.05-0.3 mm shorter than fertile lemma |
6 Ligule a ciliate or eciliate membrane (0-) 0.3-0.9 mm long; leaf blades 5-28 cm by 5-40 mm; second glume 0-0.1 mm shorter than fertile lemma. |
8 Lower sheaths papillose- hispid with spreading hairs; ligule a membrane 0.4-0.9 mm long; leaf blades 10-28 cm long |
8 Lower sheaths glabrous, puberulent, or softly villous basally; ligule either a membrane 0-0.3 mm long or a ciliate membrane 0.4-0.7 mm long; leaf blades 5-18 cm long. |
9 Ligule a ciliate membrane 0.4-0.7 mm long; leaves 15-40 mm wide; spikelets 1.6-2.0 mm wide |
9 Ligule a membrane 0-0.3 mm long; leaves 5-25 mm wide; spikelets 1.1-1.3 mm wide |
10 Cauline blades 5-18 cm long, 6-14 mm wide, averaging about 10 × as long as wide, the margins nearly parallel; spikelets 2.9-3.7 mm long; first glumes 1.1-2.6 mm long, 2/5 or more as long as the spikelets |
10 Cauline blades 7-12 cm long, (6-) 12-25 mm wide, ovate- lanceolate, averaging about 6 × as long as wide, the margins curved most of their length; spikelets 2.0-3.2 mm long; first glumes 0.5-1.0 mm long, about 1/4 as long as spikelets. |
11 Culms erect; blades more nearly symmetrical; spikelets 2.0-3.2 mm long; sterile lemma apex usually blunt to rounded |
11 Culms basally decumbent; blades strongly asymmetrical- falcate; spikelets 3.0-3.2 mm long; sterile lemma apex usually pointed |
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2 Leaf blades, at least the lower, cordate or subcordate at the base, 4-25 mm wide. |
3 Culm blades 4-12 mm wide; spikelets obpyriform when viewed dorsally, strongly plano- convex when viewed laterally, usually markedly reddish-purple basally; fertile lemma papillose |
3 Culm blades 5-25 mm wide; spikelets elliptic to elliptic- obovoid when viewed dorsally or laterally, greenish to faintly purple-tinged basally; fertile lemma not papillose. |
4 Ligule ciliate, 0.2-0.8 mm long; culm blades 5-14 mm wide; spikelets 1.8-2.6 mm long; first glumes 0.5-1 mm long |
4 Ligule an eciliate membrane 0-0.3 mm long; culm blades 5-25 cm wide; spikelets 2.0-3.7 mm long; first glumes 0.5-2.6 mm long. |
5 Internodes crisp- puberulent; larger culm blades 4-8 (-11) cm long, 5-10 (-12) mm wide, broadest near the base; spikelets 2.1-2.7 mm long; first glumes 0.7-0.9 mm long |
5 Internodes glabrous to sparsely pubescent, larger culm blades 5-18 cm long, 5-25 mm wide, broadest near the middle or broadly linear; spikelets 2.0-3.7 mm long; first glumes 0.5-2.6 mm long. |
6 Cauline blades 5-18 cm long, 6-14 mm wide, averaging about 10 × as long as wide, the margins nearly parallel; spikelets 2.9-3.7 mm long; first glumes 11-26 mm long, 2/5 or more as long as the spikelets |
6 Cauline blades 7-12 cm long, (6-) 12-25 mm wide, ovate- lanceolate, averaging about 6 × as long as wide, the margins curved most of their length; spikelets 2.0-3.2 mm long; first glumes 5-10 mm long, about 1/4 as long as spikelets. |
7 Culms erect; blades more nearly symmetrical; spikelets 2.0-3.2 mm long; sterile lemma apex usually blunt to rounded |
7 Culms basally decumbent; blades strongly asymmetrical- falcate; spikelets 3.0-3.2 mm long; sterile lemma apex usually pointed |
2 Leaf blades tapering to the base, 2-12 mm wide. |
8 Ligule a stramineous to light brown membrane, with or without terminal cilia. |
9 Ligule a ciliate membrane; spikelets (2.6) 2.8-3.4 (3.6) mm long; first glume (0.9) 1.1-1.6 mm long |
9 Ligule an eciliate membrane; spikelets 1.6-2.8 (3.0) mm long; first glume 0.3-1.1 mm long. |
10 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 |
10 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. |
11 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 |
11 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 |
8 Ligule of short white hairs or absent. |
12 Leaves basally disposed, usually matted or cushion-forming, larger than the mid and upper culm leaves; blade margins uniformly papillose- ciliate; culms branching only at the base, 0.5-3.5 dm tall; internodes glabrous or sparsely pubescent |
12 Basal leaves usually rosette-forming, not matted or cushion-forming, usually much smaller than culm leaves; blade margins glabrous, or ciliate only below the middle (or sometimes papillose- ciliate throughout in D. portoricense ssp. patulum, which has densely puberulent internodes); culms branching at the nodes in age, 1.5-7.5 dm tall. |
13 Blades progressively longer upwards on culm, the larger 9-20 cm long and 3-8 mm wide, (15-) 20 × or more as long as wide, firm but not stiff, not longitudinally grooved or wrinkled; blade adaxial surface (weakly-) strongly scabrous; sheaths glabrous; second glume and sterile lemma exceeding fertile lemma |
13 Blades similar or more often decreasing in size upwards on culm, the larger 3-16 cm long and 2-25 mm wide; if 15 × or more as long as wide, then blades stiff and longitudinally grooved or wrinkled (sect. Angustifolia); blade adaxial surface smooth to moderately scabrous; sheaths glabrous or pilose; second glume and sterile lemma shorter than to exceeding fertile lemma. |
14 Blades of mid- culm leaves typically long and stiff, acuminate, linear or narrowly lanceolate, usually > 10× as long as wide, only 2-6 mm wide when < 8 cm long. |
15 Vegetative parts glabrous (spikelets pubescent, lowest internodes and sheaths sometimes sparsely pubescent, blades and sheaths sometimes ciliate); mature panicles less than ¼ as wide as long, the branches erect- ascending, the spikelets often subsecund; autumnal blades 4-10 cm long, involute, < 2 mm wide; spikelets 1.8-2.2 mm long. |
16 Larger vernal blades 5-8 cm long and 3-5 mm wide; vernal panicles usually less than ¼ as wide as long, spikelets often subsecund along the strongly ascending to erect branches; spikelets 1.8-2.2 mm long, second glume and sterile lemma pubescent, summits blunt, about equaling fertile lemma; [of coastal wetlands and Piedmont prairies from NC and AR south to the Caribbean and Central America] |
16 Larger vernal blades 5-9 cm long and 2-3 mm wide; vernal panicles usually ¼ to ½ as wide as long, the branches ascending; spikelets 2.3-3.0 mm long, second glume and sterile lemma sparsely pubescent to glabrous, summits pointed to blunt, exceeding fertile lemma; [of c. and s. FL] |
15 Vegetative parts pubescent, at least in the lower portion of plant; mature panicles usually more than half as wide as long, the branches spreading- ascending, the spikelets not noticeably subsecund; autumnal blades 1-6 cm long, involute and < 2 mm wide in D. aciculare and D. arenicoloides, or to 9 cm long, flat and 2-4 mm wide in D. angustifolium ( autumnal blade dimensions not yet known for D. wilcoxianum); spikelets 1.5-3.2 mm long. |
17 Culms 15-35 cm long; all culm leaf blades long- hirsute on both surfaces, their sheaths densely papillose- hirsute; leaf blades of the primary branches often exceeding the immature vernal panicles |
17 Culms 15-75 cm long; culm leaf blades glabrous to sparsely pubescent, or the lower softly villous abaxially in D. arenicoloides; lower sheaths usually villous, mid- culm and upper sheaths glabrous (though often ciliate basally); leaf blades of primary branches not exceeding immature vernal panicles. |
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 leaf blades 3-6 mm wide, the lower and mid- culm leaf blades of similar width; autumnal leaf 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 leaf blades 2-8 mm wide, the lower usually wider and often shorter than mid- culm leaf blades; autumnal leaf blades involute or flat. |
19 Longest vernal blades to 16 cm, widest vernal leaf blades 4-8 mm, usually longitudinally wrinkled; vernal and autumnal spikelets 2.3-3.1 mm long; autumnal leaf blades flat, the larger to 9 cm by 2-4 mm |
19 Longest vernal leaf blades to 6 cm ( D. aciculare ) or 12 cm ( D. arenicoloides) 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 leaf blades involute, the larger to 6 cm by 1.5 mm. |
20 Longest vernal leaf blades to 12 cm, widest vernal leaf 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 leaf blades to 6 cm by 1.5 mm |
 Show caption*© Janet Wright, some rights reserved (CC BY-NC), uploaded by Janet Wright Longest vernal leaf blades to 6 (-8) cm, widest vernal leaf 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 leaf blades to 3 cm by 1 mm |
14 Blades of mid- culm leaves lanceolate, thin or firm but not stiff, usually < 10× as long as wide, usually 7 mm or more wide when as much as 8 cm long. |
21 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 below expansion of second glume and sterile lemma |
21 Spikelet bases not noticeably attenuate, apices rounded to acute; first glume < ½ as long as spikelet, attached < 0.3 mm below expansion of second glume and sterile lemma. |
22 Spikelets 2.9-3.8 mm long, broadly elliptic, rounded at the summit, with broad and thick nerves |
22 Spikelets 2.1-2.9 mm long, elliptic or obovate, rounded or pointed at the summit, the nerves often raised, but not broad and thick. |
23 Culm internodes and sheaths glabrous, sparsely pilose, or villous. |
24 Culms 50-150 cm long; at least lowest sheaths papillose- pilose. |
25 Lowest internodes usually purple- villous; nodes retrorsely (-spreading) bearded; spikelets 1.8-2.2 mm long, moderately densely pubescent; first glume broadly ovate, subacute, 0.4-0.7 mm long, usually < 1.5 × as long as wide; second glume about as long as sterile and fertile lemmas; fertile lemma 1.7-1.8 mm long |
25 Lowest internodes glabrous or pubescent or spreading villous, usually not purplish; nodes glabrous, sparsely pubescent to sparsely bearded; spikelets 2.2-2.8 (-3.0) mm long, sparsely pubescent; first glume 0.7-1.1 mm long, usually > 1.5 × as long as wide; second glume shorter than sterile and fertile lemmas; fertile lemma 2.1-2.2 mm long |
24 Culms 18-100 cm long; sheaths glabrous or the lowest softly pubescent but not papillose- pilose. |
26 Spikelets strongly plano- convex when viewed laterally, obpyriform when viewed dorsally, (2.1-) 2.2-2.6 mm long; fertile lemma and palea papillose or smooth; first glume usually broadened above base, rounded or broadly tapered distally; glume bases often reddish-purple. |
27 Culm leaves 2-5 mm wide; fertile lemma and palea smooth, shiny |
27 Culm leaves 4-12 mm wide; fertile lemma and palea papillose-roughened |
26 Spikelets biconvex to elliptic when viewed laterally, variously shaped but not obpyriform when viewed dorsally; fertile lemma and palea smooth or reticulate (or papillose in D. lucidum with weak and sprawling culms and spikelets 1.7-2.3 mm long); first glume usually tapered from near base to apex; glume bases various |
23 Culm internodes crisp- puberulent (sparsely so in D. webberianum); sheaths puberulent or glabrous. |
28 Spikelets elliptic, sub- acute to pointed, greenish or faintly purple-tinged basally |
28 Spikelets strongly plano- convex when viewed laterally, obpyriform when viewed dorsally, broadly rounded, usually markedly reddish-purple basally. |
29 Fertile lemma and palea papillose; spikelets 2.2-2.6 mm long; lower culm blades 6-12 mm wide, glabrous |
29 Fertile lemma and palea smooth (minutely reticulate but not papillose); spikelets (1.8) 1.9-2.2 (-2.5) mm long; lower culm blades 2-8 mm wide, glabrous, glabrate, or puberulent (especially abaxially) |
