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Key to Dichanthelium, Key F: Spikelets 0.8-2.0 mm long, lower culm internodes variously hairy

Poaceae

Dichanthelium

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1 Longer hairs of ligule 2-5 mm long.
  2 Ligule with a distinct ring of short hairs in front of the long hairs.
    3 Peduncle, panicle axis, and sheaths puberulent with hairs 0.1 mm long; larger blades 3-6 cm long, 3-5 mm wide; spikelets 1.3-1.7 mm long
    3 Peduncle, panicle axis, and sheaths pubescent with hairs more than 0.1 mm long; larger blades 12-20 cm long, 7-9 mm wide; spikelets 1.9-2.3 mm long
  2 Ligule without a distinct ring of short hairs in front of the long hairs.
      4 Culms > 100 cm long; node pubescence densely retrorse; larger blades 12-20 cm long; vernal spikelets 1.9-2.3 mm long, nearly 2× as long as wide; autumnal spikelets 2.2-2.5 mm long, > 2× as long as wide
      4 Culms < 100 cm long (-rarely longer); node pubescence various; larger blades 3-12 cm long; spikelets (1.0-) 1.1-2.0 mm long, less than 2 × as long as wide, rounded to blunt.
        5 Blades of mid-culm leaves lanceolate, thin or firm but not stiff, length and width various, less than 15× as long as wide
        5 Blades of mid-culm leaves linear or narrowly lanceolate, stiff, acuminate, often involute, 4-10 cm long, 2-5 mm wide, about 15-20× as long as wide
1 Longer hairs of ligule < 2 mm long.
          6 Culm leaves basally crowded, ascending, usually matted or cushion-forming, larger than the mid and upper culm blades.
             7 Sheaths conspicuously retrorsely long-pilose; longer blades 6-18 cm long and 7-12 mm wide; spikelets (1.4-) 1.9-2.3 (-2.5) mm long
             7 Sheaths variously pubescent or glabrous, but not conspicuously retrorsely long-pilose; longer blades 2-6 cm long and 1-8 mm wide; spikelets 0.9-2.1 mm long.
               8 Leaf blades 1-4 mm wide, glabrous, the margins eciliate or basally ciliate; spikelets 0.9-1.5 mm long, glabrous; autumnal form branched from lower and mid nodes as well as from basal nodes.
                 9 Leaf blades 1.5-4 (-5) cm long; spikelets 0.9-1.2 (-1.4) mm long
                 9 Leaf blades 4-12 (-20) cm long, some at least 7 cm long; spikelets 1.2-1.5 mm long
               8 Leaf blades 2-10 mm wide, pubescent or glabrous, the margins coarsely papillose-ciliate throughout; spikelets 1.1-2.1 mm long, glabrous or pubescent; autumnal form branched from basal nodes only.
          6 Culm leaves not basally crowded, the lowest leaves spreading and rosette-forming, usually smaller than the culm leaves.
                       12 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
                       12 Blades similar or more often decreasing in size upwards on culm; if 15 × or more as long as wide, then larger blades 4-10 cm long and 2-5 mm wide, 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 equaling fertile lemma.
                          13 Blades of mid-culm leaves linear or narrowly lanceolate, stiff, acuminate, often involute, 4-10 cm long, 2-5 mm wide, about 15-20× as long as wide.
                          13 Blades of mid-culm leaves lanceolate to lance-elliptic, thin or firm but not stiff, length and width various, < 15× as long as wide.
                                16 Ligule 0.7-1.5 mm long; first glume acute; spikelets elliptic when viewed dorsally, biconvex or elliptic when viewed laterally, not strongly nerved
                                16 Ligule < 0.5 mm long; first glume obtuse to truncate; spikelets obovate when viewed dorsally, plano-convex when viewed laterally, strongly nerved.
                                       19 Internodes (sparsely-) moderately to densely pubescent to pilose; ligule 1-5 mm long; blade margins either weakly ciliate, papillose-ciliate basally only, or eciliate, lacking a white-beige cartilaginous edge 0.2 mm wide.
                                         20 Larger mid-culm blades 4-7 cm long, 4-7 mm wide, glabrous to sparsely pubescent adaxially; ligule 1-5 mm long; spikelets 1.1-1.5 mm long
                                         20 Larger mid-culm blades 3-6 cm long, 3-5 mm wide, long-pilose adaxially; ligule often with a ring of hairs < 1 mm and scattered longer hairs to 4 mm; spikelets 1.3-1.7 mm long
                                           21 Blades 5-14 cm by 5-17 mm, basally truncate to cordate, margins only ciliate basally if at all, without a white-beige margin up to 0.2 mm wide
                                           21 Blades 1.5-6 (8) cm by 2-8 mm, basally narrowed to rounded, blade margins either coarsely papillose-ciliate throughout or glabrous with a white-beige cartilaginous edge about 0.2 mm wide.

Key to Dichanthelium, Key to the Dichanthelium dichotomum group

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1 Lower cauline nodes bearded, the hairs usually retrorse.
    3 Ligule an eciliate membrane; fertile lemma and palea densely papillose at 20×; leaves 3.5-7 cm long by 3-6 mm wide; culms weak, usually sprawling over other vegetation
    3 Ligule ciliate; fertile lemma and palea smooth, with few or no papillae; leaves either 1.5-4 (-5) cm long by 1-5 mm wide, or 5-12 cm long by 3-15 mm wide.
      4 Spikelets 0.9-1.4 mm long; vernal cauline blades 1.5-4 (-5) cm long and 1-5 mm wide; internodes or sheaths glabrous or pubescent.
        5 Spikelets 0.9-1.2 (-1.4) mm long; sheaths glabrous; vernal cauline blades 1-2 (-3) mm wide; ligule < 1 mm long; node beard hairs erect and often only partially encircling the node; internodes glabrous or puberulent
        5 Spikelets 1.2-1.4 mm long; sheaths spreading-pilose; vernal cauline blades 2-5 mm wide; ligule 1-2 mm long; node beard hairs usually spreading or reflexed; internodes glabrous
      4 Spikelets 1.4-2.3 mm long; vernal cauline blades 5-12 cm long and 3-15 mm wide; internodes and sheaths glabrous.
          6 Spikelets 1.8-2.3 mm long; first glume 0.6-1.1 mm long; fertile lemma 0.8-1.0 mm wide; widest vernal blades 3-8 (-10) mm wide; nodes, often only the lower, usually sparsely to moderately bearded with retrorse hairs
          6 Spikelets 1.4-1.9 mm long; first glume 0.3-0.6 (-0.7) mm long; fertile lemma 0.6-0.8 mm wide; widest vernal blades 7-15 mm wide; usually all nodes densely bearded with retrorse hairs
             7 Spikelets 1.2-1.4 mm long; sheaths spreading-pilose; vernal cauline blades 1-4 cm long and 2-5 mm wide; ligule 1-2 mm long
             7 Spikelets 1.4-2.8 mm long; sheaths glabrous to pilose; vernal cauline blades 5-15 cm long and 5-15 mm wide; ligule ≤ 1 mm long.
               8 Culms(55-) 70-140 cm long; lowest internodes moderately to densely villous; vernal cauline leaves 6-15; blades glabrous except for basal cilia; spikelets 1.8-2.2 mm long, obovoid to broadly ellipsoid, rounded to blunt
               8 Culms 30-110 cm long; lowest internodes glabrous to sparsely hairy; vernal cauline leaves 3-7; spikelets 1.4-2.8 mm long, elliptic to lance-ovate, blunt to acute.
                 9 Usually all culm nodes bearded; internodes glabrous, or middle and upper internodes and peduncle sparsely to moderately spreading short-hairy, sometimes also glandular; upper as well as lower vernal sheaths and both surfaces of cauline blades pubescent, often densely so; spikelets (1.5-) 1.8-2.2 mm long; [of dry rocky or sandy basic soil and barrens]
                 9 Often only lower culm nodes bearded; internodes glabrous; at least middle and upper cauline blades glabrous; spikelets 1.4-2.8 mm long; [mostly of wet acid soils and mesic to dry woodlands].
                   10 Spikelets (2.0-) 2.2-2.8 mm long; first glume 0.5-1.3 mm long; fertile lemma 1.8-2.3 mm long; lowest vernal cauline blades pubescent at least abaxially
                   10 Spikelets 1.4-2.2 mm long; first glume 0.3-0.9 mm long; fertile lemma 1.4-1.7 mm long; lowest vernal cauline blades glabrous.
                     11 Spikelets 1.7-2.2 mm long; first glume 0.6-0.9 mm long; fertile lemma 0.7-1.0 mm wide
                     11 Spikelets 1.4-1.9 mm long; first glume 0.3-0.6 (-0.8) mm long; fertile lemma 0.6-0.8 mm wide
                          13 Spikelets (1.5-) 1.7-2.7 mm long, if shorter than 1.8 mm then fertile lemma and palea densely papillose; culms soon sprawling.
                            14 Spikelets (1.5-) 1.7-2.3 mm long, glabrous (rarely pubescent); first glume 0.7-1.1 mm long; fertile lemma and palea densely papillose at 20×
                            14 Spikelets 2.2-2.7 mm long, pubescent; first glume 1.0-1.4 mm long; fertile lemma and palea smooth or with a few weak papillae at 20×
                              15 Leaf blades involute and often falcate, 3-6 cm long, about 1.5 mm wide when flattened, 20-50× as long as wide; lower internodes often strigose; spikelets 1.2-1.4 mm long; culms 5-20 cm long; [endemic to c. and s. FL scrub]
                              15 Leaf blades neither involute (except apically) nor falcate, 1-7 cm long, 1.5-7 mm wide, about 10× as long as wide; lower internodes glabrous or sparsely pilose, but not strigose; spikelets 1.1-1.7 mm long; culms 15-60 cm long; [wet sites, collectively widespread in coastal plain from NJ to TX and sparsely inland]
                                16 Leaf blades (3-) 4-6 (-9) per culm, pliable, 1-3.5 (-5) cm long, 1.5-4 mm wide, the margins flat and sharp-edged, gray-green to white-beige, 0.1 mm wide or less; spikelets 1.2-1.5 mm long, pubescent or glabrous; culms to 40 cm long
                                16 Leaf blades 3-4 per culm, firm, 2-6 (-8) cm long, 2-6 (-8) mm wide, at least one margin cartilaginously thickened, the edge usually rounded, white-beige to green-stramineous, 0.1-0.2 mm wide; spikelets (1.1-) 1.3-1.7 mm long, pubescent; culms to 60 cm long
                                  17 Cauline leaves mostly basally disposed, strongly ascending, much larger than the 2-3 remote middle and upper cauline leaves of fertile culms; spikelets 2.4-2.9 mm long; culms branch from basal and lower nodes, but are not known to produce autumnal inflorescences; [Wet pine savannas and seepages; endemic to Gulf Coastal Plain]
                                  17 Cauline leaves well-distributed along the culm, > 3, gradually reduced upward and often spreading; spikelets 0.9-2.6 mm long; culms produce autumnal inflorescences from lower, middle, and/or upper nodes, if from lower only, then spikelets only 0.9-1.2 mm long; [collectively widespread, habitats various].
                                    18 Fertile lemma and palea densely papillose; ligule usually ciliate, rarely an eciliate membrane 0.1-0.3 mm long; culms weak, soon sprawling over vegetation
                                         20 Spikelets 0.9-1.2 (-1.4) mm long; blades 1.5-4 (-5) cm long, 1-2.5 (-3) mm wide, mostly 15-20 times as long as wide; autumnal plants cushion-forming
                                           21 Leaf blades 1-3 (-5) cm long, 1.5-3 (-4) mm wide, about 10 times as long as wide; autumnal plants sparsely tufted
                                           21 Leaf blades 4-12 (-20) cm long (the longer at least 7 cm), 2-4 mm wide, 20-30 (-50) times as long as wide
                                       19 Spikelets 1.4-2.6 mm long; vernal blades 3-15 mm wide (if spikelets < 1.6 mm long and vernal blades < 5 mm wide, then larger blades > 5 cm long in D. caerulescens).
                                             22 Widest vernal cauline blades 7-15 mm wide; upper sheaths often glutinous-warty; spikelets 2.1-2.6 mm long, some or most acute to beaked, second glume and sterile lemma extending 0.3-0.5 mm beyond fertile lemma in at least some spikelets
                                             22 Widest vernal cauline blades 3-10 mm wide; upper sheaths not glutinous-warty; spikelets 1.4-2.3 mm long, blunt to subacute, second glume and sterile lemma often equal to or shorter than fertile lemma, or extending < 0.3 mm beyond it.
                                               23 Spikelets 1.4-1.8 mm long; first glume 0.3-0.8 mm long; fertile lemma 1.3-1.5 mm long; mature vernal panicles usually short-exserted with ascending branches; fresh foliage bluish-glaucous
                                               23 Spikelets 1.7-2.3 mm long; first glume 0.6-1.1 mm long; fertile lemma 1.6-1.9 mm long; mature vernal panicles exserted with spreading branches; fresh foliage not bluish-glaucous.
                                                 24 Vernal panicle smooth to weakly scabrous, the scabrousness usually confined to the pedicels; vernal cauline blades spreading to deflexed, flexuous; autumnal form densely bushy-fascicled, essentially forming one large mass of clustered leaves [of wet-mesic to dry woods and thickets]
                                                 24 Vernal panicle moderately to densely scabrous, increasingly so from rachis to branches to pedicels; vernal cauline blades stiffly erect; autumnal fascicles forming isolated clusters of leaves [of wet pine savannas and open swamps]