Flora of the Southeastern United States

1 Plants perennial (cespitose or rhizomatous), with basal innovations present (these short often "stubby" offset shoots originating near the basal sheaths), and with or without buds in the basal sheaths.

  2 Palea lacking a broadened wing or tooth near its base. {Add curtipedicellata (basipetal; with innovations and short knotty rhizomes < 4 mm thick, culms viscid), lehmanniana (basipetal; with innovations at basal nodes, culms glabrous to basally scabridulous), palmeri (acropetal; with innovations and knotty bases, lacking rhizomes, culms glabrous below nodes), sessilispica (basipetal; with innovations, without rhizomes; culms glabrous below nodes), silveana (basipetal; with innovations and short knotty rhizomes < 4mm thick, culms often glandular below nodes, sometimes viscid), spicata (basipetal; with innovations, without rhizomes, culms glabrous), swallenii (acropetal; with innovations, without rhizomes, culms with glandular bands below the nodes)}

    3 Plants with short, knotty, thick rhizomes; spikelet disarticulation basipetal (the apical florets falling first then followed sequentially by lower or more proximal florets; the glumes then persisting on the inflorescence rachises)

    3 Plants without short or thick rhizomes; spikelet disarticulation acropetal (i.e., disarticulation beginning lowest with the glumes, thus the spikelets falling whole and glumes not persisting on the inflorescence rachises; paleas sometimes persistent but not both glumes).

      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.

                   10 Anthers 3.

                     11 Spikelets 4-10 (-19) mm long.

                       12 Spikelets appressed to the panicle branches, with 10-22 florets each

                       12 Spikelets erect on panicle branches, with 3-10 florets each

                     11 Spikelets 2-4.5 (-5) mm long.

                          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

                   10 Anthers 2.

                            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 2.4-5 mm wide; upper glumes 2.2-4 mm long; [native and introduced]

                                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 annual, lacking innovations or buds in the lower sheaths, growing cespitose, geniculate or mat-forming.

                                       19 Paleas prominently ciliate-pectinate on the keels, the cilia (0.1-) 0.2-0.8 mm long.

                                         20 Pedicels of the spikelets straight, 0.1-1.0 mm long, mostly shorter than the spikelets; anthers 2.

                                         20 Pedicels of the spikelets mostly curved, 1-4 (-7) mm long, ≥ the length of the spikelets; anthers 3.

                                           21 Spikelets 5-12 (-18) mm long, 1.4-2.4 mm wide, 12-42-flowered; lemmas (1.3-) 1.5-2.0 mm long, chartaceous, the apex acute

                                           21 Spikelets (1.0-) 1.5-3.5 mm long, 0.9-1.4 mm wide, 4-12-flowered; lemmas 0.7-1.1 mm long, membranous, the apex truncate to obtuse.

                                       19 Paleas smooth to scaberulous on the keels, if the latter then the scabrous projections < 0.1 mm long.

                                             22 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 Hermaphroditic; spikelets bisexual; anthers 2, each 0.2-0.3 mm long

                                               23 Dioecious; spikelets unisexual; anthers 3, each 1.4-2.2 mm long

                                             22 Plants not stoloniferous (sometimes creeping and forming flat mats); inflorescences 3-55 cm long; culms (2-) 6-130 cm tall.

                                                 24 Ligules membranous, glabrous

                                                 24 Ligules ciliate, with a row of tiny white hairs.

                                                    25 Caryopsis with a deep to shallow groove along the adaxial surface.

                                                      26 Spikelets (4-) 5-10 (-11) mm long, 5-11 (-15)-flowered; pedicels ascending, somewhat appressed along the branches.

                                                        27 Spikelets ovate to oblong in outline, >1.4 mm wide; lower glume 1.2-2.3 mm long

                                                        27 Spikelets linear to linear-lanceolate, <1.5 mm wide; lower glume 0.7-1.7 mm long

                                                      26 Spikelets (1.4-) 2-5 mm long, 2-6 (-7)-flowered; pedicels erect, spreading along the branches.

                                                          28 Panicle 10-45 (-55) cm long, 2/3 or more the height of the plant; pedicels (4-) 5-25 mm long; glandular pits absent below the nodes, branches, and rachis

                                                          28 Panicle 4-20 cm long, < ½ the height of the plant; pedicels 1.5-5 mm long; glandular pits often present below the nodes, branches, and rachis

                                                    25 Caryopsis not grooved on the adaxial surface.

                                                            29 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.

                                                              30 Spikelets (1.7-) 2-4 mm long, 3-6-flowered

                                                              30 Spikelets (2-) 3.5-20 mm long, (3-) 5-40-flowered.

                                                                 31 Spikelets 0.6-1.3 mm wide; pedicels 1-10 mm long, flexuous and delicate, appressed or spreading

                                                                 31 Spikelets 1.1-4 mm wide; pedicels 0.2-4 mm long, straight and rigid, mostly spreading.

                                                                   32 Spikelets 6-20 mm long, 2-4 mm wide, 10-40-flowered; lemmas 2-2.8 mm long, with 1-3 crateriform glands along the keel; disarticulation of the entire florets from the persistent rachilla; anthers yellow

                                                                   32 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.

                                                                     33 Inflorescence with glandular areas of spots or rings on the rachis below the panicle branch bases, the glands often shiny or yellowish; stamens 3; blade margins lacking crateriform glands

                                                                     33 Inflorescence sometimes with glandular areas of spots or crateriform pits on the rachis below the panicle branch bases, the glands usually dull and greenish-gray to straw-colored; stamens 2; blade margins sometimes with crateriform glands

                                                            29 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.

                                                                       34 Spikelets (1.6-) 2-4 mm wide, 12-42-flowered; disarticulation of entire florets from a persistent rachilla

                                                                       34 Spikelets 0.6-2.5 mm wide, 3-22-flowered; disarticulation of the lemmas only, the paleas usually persistent (or deciduous), the rachilla persistent.

                                                                         35 Spikelets 3-6-flowered

                                                                         35 Spikelets (3-) 5-42-flowered.

                                                                           36 Lemmas with conspicuous lateral veins, these usually greenish; grains 0.3-0.6 mm long, ovoid, subglobose, or obovoid.

                                                                              37 Spikelets 5-12 (-18) mm long, with 12-42 florets; primary branches 6-10 per culm; lemmas 1.3-2.0 mm long; anthers 3

                                                                              37 Spikelets 2-4.6 mm long, with 5-15 florets; primary branches (12-) 15-20 per culm; lemmas 1.0-1.3 mm long; anthers 2

                                                                           36 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.

                                                                                38 First glume 0.3-0.6 (-0.8) mm long, <0.5× as long as the lowest lemma; spikelets 0.6-1.3 mm wide; panicle branches usually whorled at the lowest 2 nodes

                                                                                38 First glume 0.5-1.5 mm long, >0.5× as long as the lowest lemma; spikelets 1.2-2.5 mm wide; panicle branches solitary or paired at the 2 lowest nodes.

                                                                                  39 Anthers 0.5-0.7 mm long; [endemic to s. FL]

                                                                                  39 Anthers 0.2-0.4 mm long; [collectively widespread in our area]

                                                                                    40 Pedicels widely spreading

                                                                                    40 Pedicels appressed or rarely diverging up to 20 degrees from the branches