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Key to Eragrostis

Poaceae

Eragrostis

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1 Plants cespitose or rhizomatous perennials, with innovations near the base, and with or without buds in the basal sheaths.
  2 Palea with a broadened wing or tooth on each side near its base that often projects beyond the lemma
  2 Palea lacking a broadened wing or tooth near its base.
    3 Plants with short, knotty, thick rhizomes; florets articulating whole
    3 Plants without short or thick rhizomes; florets usually disarticulating.
      4 Caryopsis with a deep to shallow groove along the adaxial surface.
        5 Caryopsis dorsoventrally compressed, flattened parallel to the side of the embryo, translucent, light brownish
        5 Caryopsis laterally compressed, flattened on the side perpendicular to the embryo, or cylindric, opaque (rarely translucent), usually reddish brown.
          6 Lateral veins of the lemmas conspicuous, often greenish, the lemmas strongly keeled
          6 Lateral veins of the lemmas inconspicuous and hardly evident, the lemmas sometimes weakly keeled.
             7 Lemmas 1.2-1.8 mm long; culms 30-70 cm tall
               8 Spikelets 0.5-1 (-1.3) mm wide, with a gray or reddish-purple tinge; sheaths glabrous dorsally and on the collars; distal margins of the lemma hyaline;
               8 Spikelets 1.1 -1.6 mm wide, with a gray tinge; sheaths sometimes densely pilose dorally and on the collars; distal margins of the lemmas not hyaline
             7 Lemmas 1.6-3.0 mm long; culms (30-) 40-110 (-120) cm tall.
                 9 Spikelets 2-6-flowered, greenish with purple tinges; leaf blades 3-8 (-11) mm wide, 25-60 cm long; sheaths often densely papillose-hirsute
                 9 Spikelets (3-) 5-12-flowered, olive green to lead gray; leaf blades 1-3.8 mm wide, (4-) 10-35 cm long; sheaths never papillose-hirsute
      4 Caryopsis not grooved on the adaxial surface.
                          13 Leaf blades 25-60 cm long, 3-8 (-11) mm wide; lemmas 1.6-2.4 mm long; spikelets 1.0-1.7 mm wide
                          13 Leaf blades (4-) 8-22 cm long, 1-3.5 mm wide; lemmas 1.2-1.8 mm long; spikelets 0.5-1.0 (-1.3) mm wide
                            14 Panicle 15-45 cm wide, open, diffuse, broadly ovate to obovate in outline, the panicle branches capillary; pedicels 0.5-35 (-50) mm long, longer than or shorter than the spikelets.
                              15 Spikelets with widely spreading pedicels, the lower pedicels all generally longer than the spikelets; disarticulation of the lemmas only, the paleas persistent
                              15 Spikelets with appressed pedicels, lower pedicels of each branch shorter than the spikelets; disarticulation usually of the whole floret
                            14 Panicle (1-) 2-17 (-20) cm wide, contracted to open, narrowly ovate to oblong in outline, the panicle branches stiffly spreading (appressed to stiffly spreading in E. scaligera); pedicels (0-) 0.3-6 mm long, always shorter than the spikelets.
                                16 Spikelets (0.7-) 1.3-2.4 mm wide; upper glumes 1.4-2.2 mm long; [non-natives].
                                  17 Panicles 2-12 cm long, open; leaf blades 4-8 (-18) cm long, 1-2 mm wide; [primarily s. FL]
                                  17 Panicles 15-30 cm long, open or contracted; leaf blades (8-) 12-50 cm long, 2-6 mm wide; [SC s. to FL and w. to LA].
                                    18 Panicles (4-) 8-17 cm wide; spikelets gray, occasionally with a reddish-purple tinge; [SC s. to FL and w. to LA].
                                    18 Panicles 2-8 (-10) cm wide; spikelets stramineous or gray-colored, sometimes with a reddish tinge
1 Plants cespitose, geniculate or mat-forming annuals, lacking innovations or buds in the lower sheaths.
                                           21 Panicles contracted, narrow, spike-like, usually < 1.5 cm wide; spikelets densely packed; [uncommon to common non-native SC s. to s. FL, w. to s. TX in our area]
                                           21 Panicles less appressed, somewhat spreading; 1.5-5.0 cm wide; spikelets widely separated; [uncommon non-native in s. FL]
                                               23 Plants extensively stoloniferous, creeping and forming flat mats; inflorescences 1-3.5 cm long; culms (2-) 5-12 (-20) cm tall on the erect portions.
                                               23 Plants not stoloniferous (sometimes creeping and forming flat mats); inflorescences 3-55 cm long; culms (2-) 6-130 cm tall.
                                                              30 Plants with glandular pits or bands on the culm below the nodes, on the veins of the sheath, on the margins and veins of the blade, on the rachis, on the inflorescence branches and pedicels, and/or on the midveins of the lemma and palea.
                                                                     33 Spikelets 4-7 (-11) mm long, 1.1-2.2 mm wide, 7-12 (-20)-flowered; lemmas 1.4-1.8 mm long, rarely with 1-2 crateriform glands along the keel; disarticulation of the lemmas only, the palea and rachilla usually persistent; anthers reddish-brown.
                                                              30 Plants lacking glandular pits or bands on the culm below the nodes, on the veins of the sheath, on the margins and veins of the blade, on the rachis, on the inflorescence branches and pedicels, and/or on the midveins of the lemma and palea.
                                                                              37 Lemmas with inconspicuous or moderately conspicuous lateral veins, these usually not greenish; grains 0.5-1.1 mm long, pear-shaped, obovoid, or prism-shaped.