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Key to Rhynchospora

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1 Tubercles < 3 mm long; style divided into 2 slender stigmatic branches; [subgenus Diplostylae].
  2 Inflorescence bracts 0-several, capillary to foliaceous, green throughout (stramineous in age), variously oriented.
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Show caption*© Scott Ward
    3 Bristles present, plumose (at least towards their bases); [subgenus Diplostylae; section Plumosae]
    3 Bristles absent, or present and smooth or minutely barbed.
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Show caption*© Scott Ward
      4 Bristles present, retrorsely barbed (at least towards their tips), or antrorsely barbed and straplike (flattened); [subgenus Diplostylae; section Albae]
      4 Bristles absent, or present and smooth, or antrorsely barbed and filiform.

Key to Rhynchospora, Key A: beaksedges with tubercles 3-23 mm long
[subgenus Haplostylae; sections Longirostres and Polycephalae]

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Show caption*© Jacob M. Smith
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Show caption*© Keith Bradley
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Show caption*© Jacob M. Smith
1 Spikelets arranged in globose or subglobose clusters; tubercle 3-5 mm; leaf blades 2-8 mm wide.
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Show caption*© Jacob M. Smith
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Show caption*© Jacob M. Smith
  2 Spikelets arranged in subglobose, umbel-like clusters; achene margins crimped; plants not rhizomatous; [section Longirostres]
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Show caption*© Scott Ward
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Show caption*© Scott Ward
  2 Spikelets arranged in tightly globose clusters; achene margins not crimped; plants rhizomatous; [section Polycephalae]
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Show caption*© Bruce A. Sorrie
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Show caption*© Janet Wright, some rights reserved (CC BY-NC), uploaded by Janet Wright
1 Spikelets in > 4 paniculate or corymbose clusters; tubercle 10-23 mm long; leaf blades 6-20 mm wide; [section Longirostres].
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Show caption*© Janet Wright, some rights reserved (CC BY-NC), uploaded by Janet Wright
    3 Longest bristles shorter than the achene
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Show caption*© Scott Ward
    3 Longest bristles longer than or equaling the achene.
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Show caption*© Gary P. Fleming
      4 Plants cespitose; primary clusters with 10-50 (rarely 7 or fewer) densely clustered spikelets; achene (4.5-) 5-6 mm long
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Show caption*© Mary Keim, some rights reserved (CC BY-NC-SA)
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Show caption*© Jay Horn
      4 Plants rhizomatous; primary clusters with 1-6 loosely clustered spikelets; achene (3.5-) 4.0-4.8 mm long.
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Show caption*© Scott Ward
        5 Bristles 2-8 mm long, the central bristle longest on one face, shortest or absent on the other
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Show caption*© Scott Ward
        5 Bristles 7-12 mm long, essentially of equal length

Key to Rhynchospora, Key B: beaksedges with basally-white bracts (White-bracted Sedges) [subgenus Diplostylae; section Dichromena]

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1 Plant cespitose; achene+tubercle 0.8-1.2 mm long; [only FL, OK, TX, and ? AR in our region].
  2 Keel of lower spikelet scales not ciliolate; achene tubercle with a short (0.2-0.3 mm long) beak; [OK and TX]
1 Plant rhizomatous; achene+tubercle 1.5-2.0 mm long; [relatively widespread in our region, especially Coastal Plain from se. VA to s. FL and west to s. TX, but also rarely inland].
    3 Inflorescence bracts 3-6 (-7); basal bract (1.4-) 2-5 mm wide, the white portion (2.5-) 9-25 mm long, tapering gradually into the green portion; rhizomes slender, straight, (0.6-) 0.7-1.7 (-2.1) mm in diameter; achene 1.0-1.2 mm wide; tubercle broadly truncate on achene
    3 Inflorescence bracts (5-) 6-10; basal bract 5-12 mm wide, the white portion 22-55 mm long, tapering abruptly into the green portion; rhizomes often bent and swollen at the nodes, 1.4-3.8 mm in diameter; achene 1.2-1.5 mm wide; tubercle decurrent on achene

Key to Rhynchospora, Key C: beaksedges with plumose bristles [subgenus Diplostylae; section Plumosae]

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1 Spikelets borne singly or a few together in loose clusters, some or all spikelets on slender stalks; achene 1.7-2.6 mm long, 1.2-2.0 mm wide.
  2 Achene obovoid, 1.7-2.0 mm long, 1.2-1.5 mm wide, the tubercle seated on its summit without a constriction or basal flange; longer bristles < ½ as long as the achene
  2 Achene broadly elliptic, 1.9-2.6 mm long, 1.5-2.0 mm wide, its summit constricted below a collar-like flange at the base of the tubercle; longer bristles three-fourths to exceeding the length of the achene
1 Spikelets borne several to many in clusters, none of the spikelets on slender stalks; achene 1.3-2.2 mm long, 0.9-1.7 mm wide
    3 Leaves (1-) 2-4 mm wide, slightly involute (V-shaped in ×-section) near the base; achene 1.8-2.2 mm long; [FL only].
      4 Spikelets 8-10 mm long; fertile scales 5-8 mm long; perianth bristles 5-8 mm long
      4 Spikelets 3.5-6 mm long; fertile scales 3-3.5 (-4) mm long; perianth bristles extending to about the tubercle apex
    3 Leaves 0.3-1.5 mm wide, strongly involute (and often appearing superficially terete) throughout their length; achene 1.3-2.1 mm long; [collectively more widespread].
        5 Basal sheaths shiny, dark brown; bristles longer than the tubercle; bristles plumose in a basal zone that extends 4-20% of the length of the bristle, then with a smooth zone, the terminal zone minutely denticulate; [Gulf Coastal Plain of FL, AL, and MS]
        5 Basal sheaths dull, light to medium brown; bristles shorter than the tubercle; bristles plumose in a basal zone that extends 40-90% of the length of the bristle, the terminal zone minutely denticulate (lacking a smooth middle zone); [widespread in the Atlantic and Gulf Coastal Plain from NC south to FL, west to TX]

Key to Rhynchospora, Key D: beaksedges with bristles retrorsely barbed (at least distally)
or antrorsely barbed and straplike (flattened) [subgenus Diplostylae; section Albae]

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Show caption*© Gary P. Fleming
1 Bristles 8-25, retrorsely barbed distally, antrorsely barbed proximally; spikelets white, turning tan with age.
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Show caption*© Scott Ward
  2 Spikelets with 2-3 florets; bristles 8-12; achene 1.6-2.1 mm long, 0.9-1.3 mm wide
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Show caption*© Scott Ward
  2 Spikelets with 1 floret; bristles 16-25; achene 2.0-2.4 mm long, 1.3-1.5 mm wide
image of plant
Show caption*© Gary P. Fleming
1 Bristles 6 or fewer, either retrorsely or (rarely) antrorsely barbed their entire length; spikelets variously brown, rufous, or tan (or very rarely white).
    3 Spikelets 1-fruited, the solitary achene terminating the axis; clusters 1-7, globose to turbinate.
      4 Achene body 1.3-2.0 mm long, 0.8-1.1 mm wide; tubercle 0.9-1.8 mm long.
image of plant
Show caption*© Gary P. Fleming
        5 Clusters turbinate to hemispheric (rarely subglobose), the lowest spikelets usually spreading-ascending to spreading; larger leaves usually < 2 mm wide; achene 1.5-2.0 mm long; tubercle 1.0-1.6 mm long
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Show caption*© Keith Bradley
        5 Clusters globose to subhemispheric, the lowest spikelets usually reflexed; larger leaves usually > 2 mm wide; achene 1.3-1.9 mm long; tubercle 0.9-1.8 mm long
      4 Achene body 1.7-2.4 mm long, 1.1-1.8 mm wide; tubercle 1.4-2.7 mm long.
image of plant
Show caption*© Claire Ciafré
          6 Clusters 7-14, turbinate; achene 1.9-2.1 mm long, 1.1-1.2 mm wide; tubercle 2.3-2.7 mm long, exceeding body length
          6 Clusters 1-7, globose to hemispheric; achene 1.8-2.6 mm long, 1.1-1.8 mm wide; tubercle 1.4-2.4 mm long, shorter than to equaling body length.
             7 Achene 1.1-1.2 mm wide, 1.7-1.9 long; tubercle 1.4-1.8 mm long; heads hemispheric
image of plant
Show caption*© Melanie Flood
             7 Achene 1.4-1.6 mm wide, 2.0-2.4 mm long; tubercle to 2.4 mm long; heads globular
image of plant
Show caption*© Alex de la Paz
    3 Spikelets 1-5 fruited (if 1-fruited, then the axis terminated by a sterile floret); clusters 2-many, ovoid to turbinate (rarely globose).
               8 Clusters numerous, usually 20 or more; tubercle 1.3-1.8 mm long; achene 0.9-1.5 mm wide, 1.5-2.0 mm long, the summit narrowly truncate, the faces umbonate, the margin thickened and wire-like; leaves 2.5-7 mm wide.
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Show caption*© Jake Smith
                 9 Achene face medium brown, body 0.9-1.1 mm wide, the expanded portion above the gynophore 1.0-1.1 mm long, the gynophore slender and long
image of plant
Show caption*© Scott Ward
                 9 Achene face dark brown, body 1.2-1.5 mm wide, the expanded portion above the gynophore 1.3-1.4 mm long, the gynophore thick and short
               8 Clusters 2-8; tubercle 0.4-1.2 mm long; achene 0.6-1.2 mm wide, 1.1-2.0 mm long, the summit more rounded than truncate, the faces lenticular, a wire-like margin narrow or not evident; leaves 0.2-3.5 mm wide.
image of plant
Show caption*© Claire Ciafré
                   10 Achene 0.6-0.8 mm wide, 1.1-1.3 mm long; tubercle 0.4-0.6 mm long; bristles more-or-less equaling the achene; [Endemic to NJ and historically also DE]
                   10 Achene 0.8-1.2 mm wide, 1.3-2.0 mm long; tubercle 0.8-1.6 mm long; bristles more-or-less equaling the tubercle; [collectively widespread].
image of plant
Show caption*© Erik Danielson
                     11 Inflorescence typically with 1 terminal and 1 lateral cluster, the clusters ovoid, with 1-10 spikelets each; achene 1.8-2.0 mm long, 0.8-1.0 mm wide, 2-3 × as long as wide; leaves 0.2-0.4 mm wide
                     11 Inflorescence with 1-6 lateral clusters, the clusters turbinate with usually > 10 spikelets; achene 1.3-1.8 mm long, 0.9-1.2 mm wide, 1.5-2 × as long as wide; leaves 1.5-3.5 mm wide.
image of plant
Show caption*© Claire Ciafré
                       12 Longer bristles 0.4 mm shorter than to 0.3 mm longer than the tubercle; tubercle 0.9-1.4 (-1.6) mm long, on average 0.69× as long as achene body; glomerules 3-5 (-6), 6-13 mm wide; [widespread in our area]
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Show caption*© Scott Ward
                       12 Longer bristles 0.3-1.0 mm longer than the tubercle; tubercle 0.8-1.1 mm long, on average 0.57× as long as achene body; glomerules 4-8, 4-8 mm wide; [of the Coastal Plain]

Key to Rhynchospora, Key E: beaksedges with bristles smooth, or antrorsely barbed and filiform,
or absent, the achene surface smooth, minutely pitted, or finely striate
[subgenus Diplostylae; sections Chapmaniae, Fasciculares, and Fuscae]

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1 Bristles 12; [section Fasciculares]
1 Bristles 6 or fewer.
  2 Leaves with a short taper at the tip, blunt to acute, but not long-acuminate; achene surface minutely pitted near the margin; [section Chapmaniae].
    3 Basal leaves 4-6 mm wide, ciliate, rosulate; scales acuminate, the midrib ciliate; bristles 6, < ½ the length of the achene; achenes 1.6-2 mm long; [widespread in mesic to wet pinelands from VA s. to FL, w. to e. LA]
    3 Largest basal leaves 2.5-3 mm wide, eciliate, not rosulate; scales aristate, the midrib eciliate; bristles 3-4, 1 or more equaling or exceeding the tubercle; achenes (1.4-) 1.5-1.7 (-1.9) mm long; [rare, s. GA, disjunct in se. SC]
  2 Leaves long-acuminate at the tip; achene surface smooth or finely striate.
      4 Bristles absent or 1-3 rudimentary; scales white to pale tan (or pale reddish-brown in R. brachychaeta); [section Chapmaniae].
        5 Inflorescence composed of (1-) 2-3 turbinate to ellipsoid clusters; spikelets pale reddish-brown, (2.7-) 3-3.5 mm long; achenes usually 2 per spikelet
        5 Inflorescence composed of 1 (-2) hemispheric to broadly turbinate cluster(s); spikelets white to pale brown, either 2-2.5 (-3) mm or (3.5-) 4-5.5 mm long; achenes 1 per spikelet.
          6 Base of plant not bulb-like, not enclosed in bladeless sheaths; spikelets 2-2.5 (-3) mm long; achene 1.0-1.2 mm long, 0.8-1.0 mm wide
          6 Base of plant bulb-like, enclosed in bladeless sheaths; spikelets (3.5-) 4-5.5 mm long; achene 1.4-1.8 mm long, 1.2-1.5 mm wide
      4 Bristles present (if rudimentary, then 4-6); scales tan, rufous, or brown.
             7 Achene 0.6-1.1 mm wide, pyriform, obovoid, or narrowly elliptic, pale to dark brown but not blackish; tubercle margin setose.
               8 Inflorescence of (1-) 2-4 (-10) clusters; tubercle 0.4-1.4 mm long, the margin setose; [section Fuscae].
                 9 Achene narrowly elliptic or narrowly obovoid, 1.2-1.5 mm long by 0.6-0.7 mm wide, twice as long as wide; tubercle 0.8-1.2 mm long
                 9 Achene broadly elliptic to obovoid or pyriform, < 2× as long as wide; tubercle 0.4-1.5 mm long.
                   10 Leaves 2-4 (-5) mm wide; stipe subtending achene 0.5-1.0 mm long
                   10 Leaves 0.2-1.5 (-2) mm wide; stipe subtending achene < 0.4 mm long.
                     11 Leaves to 1.5 (-2) mm wide; achene 1.0-1.7 mm long, 0.9-1.1 mm wide; tubercle 0.5-1.5 mm long, triangular-subulate, the margins typically conspicuously concave.
                       12 Culms solitary to loosely cespitose by slender rhizomes; terminal internode straight; clusters turbinate to ovoid; achene 1.0-1.3 mm long, uniformly medium to dark brown; tubercle 0.7-1.5 mm long; bristles usually of two lengths, some equaling the tubercle, and some equaling or shorter than the achene
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Show caption*© Scott Ward
                       12 Culms solitary to cespitose, without slender rhizomes; terminal internode often arched; clusters corymbose to hemispheric; achene 1.3-1.7 mm long, pale to reddish-brown, often translucent centrally, with a distinctly thickened wire-like margin; tubercle 0.5-1.0 mm long; all bristles more-or-less equaling the tubercle
                     11 Leaves filiform, < 1 mm wide; achene 0.8-1.3 mm long, 0.6-0.9 mm wide; tubercle 0.4-0.8 mm long, deltoid to triangular-subulate, the margins flat to concave.
                          13 Plants with delicate, long-creeping rhizomes; spikelets 5-7 mm long; achene uniformly opaque; tubercle 0.6-0.8 mm long
                          13 Plants without rhizomes; spikelets 2.5-5 mm long; achene translucent centrally; tubercle 0.4-0.7 mm long.
                            14 Achenes 1.5-1.9 mm long, 0.5-0.8 mm wide; stipes 0.2-0.3 mm long; tubercles 0.4-0.6 mm long
                            14 Achenes 2.1-2.3 mm long, 0.8-0.9 mm long; stipes 0.3-0.4 mm long; tubercles 0.6-0.7 mm long
             7 Achene > 1 mm wide (except 0.8 mm wide in R. fernaldii with a blackish surface), suborbicular or broadly ellipsoid; tubercle margin smooth or roughened but not setose; [section Fasciculares].
                              15 Achene 1.3-4.2 mm long, 1.1-3.6 mm wide, brown to dark brown.
                                         20 Larger leaves to 1 mm wide; mature culms to 4.5 dm long; floral fascicles 1 (-2); tubercle 0.2-0.5 mm long
                                         20 Larger leaves 2-4 mm wide; mature culms to 13 dm long; floral fascicles (1-) 2-4; tubercle 0.4-0.7 mm long
                                           21 Basal leaves filiform to (rarely)1.3 mm wide, the longer approaching length of culm; tubercle narrowed above the base into a strap-like beak
                                             22 Longer bristles equaling to exceeding the achene body; achene body elliptic, 1.1-1.3 mm wide; tubercle triangular-attenuate; larger basal leaves 1.3-2.5 mm wide
                                             22 Longer bristles < ½ as long to exceeding achene body; achene suborbicular, 1.2-1.5 mm wide; tubercle triangular; larger basal leaves 2-4 mm wide

Key to Rhynchospora, Key F: beaksedges with bristles smooth, or antrorsely barbed and filiform, or absent,
the achene surface transversely ridged, rugose, or honeycombed-reticulate
[subgenus Diplostylae; sections Globulares, Harveyae, Mixtae, Psilocarya, Pusillae, Rariflorae]

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1 Bristles absent (or apparently so at 10×); achene 0.5-0.7 mm wide; tubercle 0.1-0.2 mm long, skull-cap like; [section Pusillae].
  2 Achene including tubercle 1.0-1.2 mm long, the achene surface evidently reticulate and obscurely transversely ridged, the body ellipsoid; bristles present, white, barely visible at 20×, the longest shorter than the achene body
  2 Achene including tubercle 0.6-0.9 mm long, the body obovoid; bristles absent.
    3 Achene surface smooth, faintly reticulate, not transversely ridged
    3 Achene surface rough, distinctly transversely ridge
1 Bristles present or absent; if absent, then the achene > 1 mm long or > 0.7 mm wide, and tubercle triangular to subulate.
      4 Culms and leaves filiform.
        5 Achene including tubercle 1.0-1.2 mm long; tubercle minute, skullcap-like; [section Pusillae]
        5 Achene including tubercle 1.5-2.9 mm long; tubercle triangular to triangular-acuminate; [section Rariflorae].
          6 Bristles subequaling to exceeding the tubercle; tubercle 0.75-1.4 mm long
          6 Bristles shorter than the achene body; tubercle 0.3-1.0 mm long.
             7 Achene 1.3-1.6 mm long, 0.9-1.4 mm wide; tubercle 0.3-0.6 (-0.75) mm long; bristles 1/3-1/2(-4/5) as long as achene body
             7 Achene 1.6-1.8 mm long, 1.35-1.5 mm wide; tubercle 0.6-1.0 mm long; bristles 2/3 to nearly as long as achene body
      4 Culms stouter; leaves wider, not filiform.
               8 Achene faces flat or concave; when one face is concave, the opposite face is sometimes slightly convex (slightly biconvex R. decurrens and R. microcarpa are keyed here for convenience).
                 9 Achene at least twice as long as wide, elliptic-oblong; tubercle subulate, 0.8-1.2 mm long; [section Mixtae]
                 9 Achene < twice as long as wide, obovate; tubercle triangular, 0.2-0.9 mm long.
                   10 Longer bristles exceeding the achene body.
                     11 Achene ±2.2 mm long, ±1.8 mm wide; tubercle ±0.9 mm long; [section Globulares]
                     11 Achene 0.8-1.2 mm long, 0.7-1.2 mm wide; tubercle 0.2-0.5 mm long; [section Mixtae].
                       12 Larger leaves (3-) 4-6 mm wide; bristles exceeding tubercle; achene faces flattened
                       12 Larger leaves 1-3 (-4) mm wide, bristles half as long as achene to equaling tubercle; achene faces slightly convex
                   10 Longer bristles shorter than to equaling achene body, or absent.
                          13 Larger leaves 3-5 mm wide; achene 1.4-1.6 mm wide; tubercle 0.6-0.8 mm long, abruptly rising from a flaring basal collar; [section Globulares]
                          13 Larger leaves 1-3 (-4) mm wide; achene 0.7-1.3 mm wide; tubercle 0.15-0.5 mm long, without a flaring basal collar; [section Mixtae].
                            14 Bristles evident, at least 1/4 as long to exceeding achene.
                              15 Culms 20-50 cm long; leaves 1-2 mm wide; bristles ½ or less as long as achene body
                              15 Culms 50-110 cm long; leaves (1-) 2-4.5 mm wide; longer bristles more than ½ as long to exceeding achene body.
                                16 Achene 1.3-1.8 mm long, 0.9-1.2 mm wide, the faces flat with 10-12 transverse ridges
                                16 Achene 0.8-1.4 mm long, 0.7-1.2 mm wide, the faces slightly biconvex with 6-12 transverse ridges.
                                  17 Clusters elongate; achene 1.0-1.4 mm long, 0.8-1.0 mm wide, narrowly obovate to elliptic, averaging 8-12 transverse ridges; most tubercle bases convexly seated on the achene summit and somewhat decurrent along the achene margins, the tubercle surface often whitish-waxy
                                  17 Clusters usually compact; achene 0.8-1.2 mm long, 0.7-1.2 mm wide, suborbicular to elliptic, averaging 6-7 transverse ridges; most tubercle bases flat across the achene summit, not decurrent, the tubercle surface usually dark, not waxy
                                    18 Achene 1.4-4.2 mm long, 1.2-3.6 mm wide, the summit with a thickened bony to crustaceous rim surrounding the base of the tubercle; [section Harveyae].
                                       19 Achene tumid, lightly pitted or cancellate in a honeycomb pattern, 1.5-4.2 mm long, 1.4-3.6 mm wide.
                                    18 Achene 0.7-1.8 mm long, 0.7-1.5 mm wide, the summit without a textured rim surrounding the base of the tubercle (if the base of the tubercle is rim-like, then it is distinguished from the summit of the achene by a constriction or articulation).
                                                 24 Spikelets (5-) 6-10 mm long, tan or brown, with an acuminate tip; tubercle ends upturned away from the achene at about a 90 degree angle
                                             22 Bristles present (occasionally detached in R. decurrens and R. miliacea with achenes 1.0-1.4 mm long); achene 0.8-1.9 mm long.
                                                      26 Cluster branches flexuous; bristles one-half as long to equaling the achene (or longer in R. microcarpa); [section Mixtae].
                                                        27 Clusters elongate; spikelets 2.5-3.5 mm long; achene narrowly obovate to elliptic, averaging 8-12 transverse ridges; most tubercle bases convexly seated on the achene summit and somewhat decurrent along the achene margins, the tubercle surface often whitish-waxy
                                                        27 Clusters usually compact; spikelets 1.5-3.0 mm long; achene suborbicular to elliptic, averaging 5-8 transverse ridges, most tubercle bases flat across the achene summit, not or only slightly decurrent, the tubercle surface usually dark, not waxy.
                                                          28 Inflorescence occupying the upper ¼-½ of the culm, the lowest 2-4 nodes barren; spikelets 2.0-3.0 mm long, ovoid, acute; achene body averaging (7-) 8 horizontal ridges; tubercle 0.25-0.85 mm long
                                                          28 Inflorescence occupying the upper 2/3-3/4 of the length of the culm, the lowest lateral panicle at the first or second node above the base; spikelets 1.5-2.25 mm long, broadly ovoid to suborbicular, apically rounded; achene body averaging 5-6 (-7) horizontal ridges; tubercle 0.2-0.4 mm long
                                                      26 Cluster branches stiff, bristles < 1/3 to ¾ (-1) × as long as achene body; [section Globulares].
                                                              30 Larger culm leaves to 5 mm wide; achenes (1.2-) 1.4-1.6 (-1.9) mm long, (1.1-) avg. 1.4 (-1.75) mm wide; achene surface alveoli longitudinally narrow; tubercle 0.3-0.7 mm long, base 0.6-1.0 mm wide
                                                              30 Larger culm leaves to 3 mm wide; achenes (1.0-) avg. 1.3 (-1.5) mm long and wide; if achene surface alveoli longitudinally narrow, then tubercle 0.2-0.4 mm long and base 0.5-0.7 mm wide (R. globularis).
                                                                 31 Longer bristles ⅓-½ (-¾)× the length of the achene; achene surface alveoli longitudinally narrow (typically 0.02-0.05 mm wide between the longitudinal walls), the latitudinal walls raised into horizontal ridges; tubercle 0.2-0.4 mm long, the base 0.5-0.7 mm wide
                                                                 31 Longer bristles ⅔-1× the length of the achene; achene surface alveoli nearly as wide as long (typically 0.05-0.1 mm wide between the longitudinal walls), the latitudinal walls obscurely or not at all raised into horizontal ridges; tubercle 0.35-0.7 mm long, the base 0.7-0.9 mm wide
                                                                   32 Primary branches of the inflorescence spreading at right angles from the culm, each spikelet or small cluster on slender spreading or reflexed stalks; [section Mixtae]
                                                                       34 Tubercle 0.4-0.8 mm long, the edges setose or uneven with waxy or crusty irregular protuberances; [section Mixtae].
                                                                           36 Spikelets 2.5-3 mm long; longer bristles about equaling the tubercle; achene 0.8-1.2 mm long, 0.7-1.2 mm wide; [section Mixtae].
                                                                              37 Inflorescence occupying the upper ¼-½ of the culm, the lowest 2-4 nodes barren; spikelets 2.0-3.0 mm long, ovoid, acute; achene body averaging (7-) 8 horizontal ridges; tubercle 0.25-0.85 mm long
                                                                              37 Inflorescence occupying the upper 2/3-3/4 of the length of the culm, the lowest lateral panicle at the first or second node above the base; spikelets 1.5-2.25 mm long, broadly ovoid to suborbicular, apically rounded; achene body averaging 5-6 (-7) horizontal ridges; tubercle 0.2-0.4 mm long
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