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Key to Sphenopholis

Poaceae

Sphenopholis

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1 Spikelets often in pairs with one subsessile and one pedicellate floret (or a mix of both if 3 florets present within a spikelet); awns of the lemma arising from midway to just below the lemma apices; lemma apices bifid; plants annual
1 Spikelets pedicellate; if awns present, then arising from just below the lemma apices; lemma apices bifid or not; plants usually perennial, rarely winter annuals.
  2 Spikelets 5-9.5 mm long; second lemma with an awn 3.5-7 mm long
  2 Spikelets 1.5-5 (-5.2) mm long; second lemma awnless, or infrequently with an awn up to 1 mm long (S. nitida) or 3.5-4 mm long (S. filiformis, S. ×pallens), but otherwise awnless.
    3 Lower leaf blades usually involute, mostly (10-) 15-45 cm long, < 2 mm wide
    3 Lower leaf blades flat, mostly < 10 cm long (8-18 cm long in S. longiflora), 2-10 mm wide.
      4 First glume 1/3-2/3 as wide as the second glume; second lemma strongly scabrous
      4 First glume ≤ ⅓ as wide as the second glume; second lemma smooth to slightly scabrous (scabridulous).
        5 First (proximal) lemma with an awn up to 3.5 mm long; distal lemma with awns 0.1-4 mm long
        5 Both first (proximal) and distal lemma unawned.
          6 Spikelets 4-5.2 mm long; panicles nodding, not spikelike; spikelets loosely arranged
          6 Spikelets 2.1-4 mm long; panicles nodding or erect, spikelike or not spikelike; spikelets loosely or densely arranged.
             7 Panicle open; second glume 3-6× as long as wide, acute at the tip; lowermost rachilla internode 0.8-1.0 mm long
             7 Panicle densely cylindrical; second glume 2-3× as long as wide, rounded or truncate at the tip; lowermost rachilla internode 0.5-0.7 mm long