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Key to Eriochloa

Poaceae

Eriochloa

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1 Spikelets 2.0-2.5 mm wide; plants annual; rachises of the inflorescence conspicuously villous; spikelets solitary towards the middle of the panicle branches
1 Spikelets 0.9-1.9 mm wide; plants perennial or annual (E. acuminata var. acuminata and E. contracta); rachises of the inflorescence glabrous, scabrous or variously pubescent (including villous); spikelets either solitary or arranged in pairs/triplets towards the middle of the panicle branches.
  2 Spikelets solitary towards the middle of the panicle branches.
    3 Panicle 0.3-1.5 cm wide, tightly contracted; second glume awned (E. contracta) or if unawned then the lower glume also absent (as in E. sericea); spikelets 8-20 per (primary) panicle branch.
      4 Lemma of fertile floret with an awn > 0.2 mm long; spikelets with 2 apparent glumes, the second (upper) glume with awns 0.4-1.1 mm long; plants cespitose annuals
      4 Lemma of fertile floret unawned; spikelets with the lower glume absent, the second and only apparent glume unawned; plants cespitose perennials with short rhizomes
    3 Panicle 2.5-10 cm wide, the branches appressed to spreading; both glumes present and unawned (rarely mucronate); spikelets 16-40 per (primary) panicle branch.
  2 Spikelets arranged in pairs or triplets towards the middle of the panicle branches.
          6 Spikelets acuminate, the upper lemmas with awns 0.4-1.5 mm long (the upper glumes often also awned or mucronate).
             7 Plants cespitose annuals (with roots only, no rhizomes although sometimes rooting from the lower cauline nodes); spikelets long-acuminate or tapering to a short awn; lower glumes absent (the upper and only apparent glume either unawned or with awns to 1.2 mm long)
             7 Plants perennials, cespitose or rhizomatous (E. punctata sometimes resembling an annual but still with [node-bearing] rhizomes); spikelets acuminate, sometimes mucronate; lower glumes present
               8 Culms erect, 40-80 cm tall; panicles 0.3-1.0 cm wide, the branches each with 2-40 spikelets and the pedicels with some hairs distally but not uniformly hirsute; upper glumes ca. 1-1.3x as long as the lower lemmas
               8 Culms erect or decumbent, 30-150 cm tall (or long if decumbent); panicles 1-10 cm wide, the branches each with 28-60 spikelets and the pedicels uniformly hirsute; upper glumes equaling the lower lemmas
          6 Spikelets acute, the upper lemmas unawned (except 0.1-0.6 mm long in E. michauxii; E. polystachya sometimes with a mucro < 0.2 mm long), upper glumes never awned (rarely mucronate in E. michauxii).
                 9 Culms decumbent, rooting at the lower nodes (plants with well-developed stolons); spikelets 3.2-3.9 mm long; spikelets {xxxx} per panicle branch
                 9 Culms erect, not rooting at the lower nodes (plants with rhizomes but lacking stolons); spikelets 3.7-5.7 mm long; spikelets 16-40 per (primary) panicle branch.
                   10 Lower florets sterile; blades involute or conduplicate, 5-8 mm wide