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Key to Schizachyrium

Poaceae

Schizachyrium

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1 Leaf blades 0.5-1.5 mm wide, with a lighter-colored zone (of bullate cells) in the center of the upper surface; sessile spikelet 3.5-4.5 mm long
1 Leaf blades >1.5 mm wide, lacking a distinct lighter zone on the upper surface; sessile spikelet 4-11 mm long.
  2 Pedicels straight, not curving outwards, the raceme therefore appearing straight and strict; pedicel bases 0.2-0.5 mm in diameter, flaring upwards to a diameter 0.3-1.0 mm wide; first glume of sessile spikelet pubescent, scabrous, or glabrous
  2 Pedicels curving outwards, the raceme therefore appearing broader and less strict; pedicel bases 0.1-0.2 mm in diameter, flaring upwards to a diameter of ca. 0.5 mm; first glume of sessile spikelet glabrous or scabrous.
    3 Plants rhizomatous, with internodes 6 mm long or longer; sessile spikelet 5-7 mm long
      4 Leaves mostly cauline, not strongly reduced, cauline leaf blades spreading to ascending; leaf blades 1-3 mm wide, usually sharply folded (V-shaped) or involute; culms usually < 1 mm in diameter, to 9 dm tall; pedicellate spikelets with awns with awns 0-1 mm long; [pine rocklands, marl prairies, wet prairies, s. FL]
      4 Leaves mostly basal, cauline leaves reduced, ascending; Leaf blades 3.5-9 mm wide, flat to slightly folded; culms usually 1-3 mm in diameter, 5-21 dm tall; pedicellate spikelets with awns 1-4 mm long; [pinelands from SC south to s. FL, west to MS]
    3 Plants cespitose, rhizome internodes absent or < 3 mm long, the stem sometimes decumbent at the base and rooting at the lower nodes (appearing nearly rhizomatous); sessile spikelet 6-10 mm long.
        5 Leaf sheaths broad and strongly keeled, hairs of the raceme internodes 2.5-6 mm long; stems decumbent at base, rooting at the lower nodes; plants blue-green.
          6 Ligules 1.5-2 mm long; pedicellate spikelets 1.5-5 mm long; [of the Atlantic Coast]
          6 Ligules 0.5-1 mm long; pedicellate spikelets 4.5-8.5 mm long; [of the Gulf Coast]
        5 Leaf sheaths rounded or weakly keeled; hairs of the raceme internodes either 1-3 (-4) mm long, or to 9 mm long (in S. gracile var. gracile and S. sericatum of s. FL); stems erect, not rooting at the lower nodes; plants green or blue-green.
             7 Sessile spikelets 5-6.5 mm long, 0.4-0.6 mm wide; pedicellate spikelets 0.5-2.0 mm long; leaf blades 2.5-10 cm long, mostly cauline, spreading
             7 Sessile spikelets 4-10 mm long, 0.6-1.2 mm wide; pedicellate spikelets 0.7-10 mm long; leaf blades 7-100 cm long, basally disposed, strongly ascending.
               8 Sessile spikelets 4-6 mm long; hairs of the raceme internodes to 9 mm long; [of s. peninsular FL].
                 9 Inflorescence with only a few branches; raceme with 7-10 dispersal units; leaf blades involute and filiform, < 1 mm wide
                 9 Inflorescence densely branched; raceme with ca. 12 dispersal units (= spikelet pairs); leaf blades flat or folded, 1-4 mm wide
               8 Sessile spikelets 6-10 mm long; hairs of the raceme 1-3 (-4) mm long; [collectively widespread, though not in s. peninsular FL].
                   10 Pedicellate spikelets of the proximal spikelet units on each raceme staminate, 5-10 mm long, with a lemma, the pedicellate spikelets of the distal units usually smaller (1-4 mm long) and sterile; sheaths and blades densely tomentose to glabrate