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Key to Eragrostis

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Show caption*© Jay Horn 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  Eragrostis superba

2 Palea lacking a broadened wing or tooth near its base.

Show caption*© Jay Horn     3 Plants with short, knotty, thick rhizomes; florets articulating whole  Eragrostis spectabilis

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  Eragrostis curvula

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  Eragrostis trichodes

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  Eragrostis lugens

7 Lemmas 1.6-3.0 mm long; culms (30-) 40-110 (-120) cm tall.

8 Spikelets 2-6-flowered, greenish with purple tinges; leaf blades 3-8 (-11) mm wide, 25-60 cm long; sheaths often densely papillose-hirsute  Eragrostis hirsuta

8 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  Eragrostis intermedia

4 Caryopsis not grooved on the adaxial surface.

9 Stamens 3.

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

11 Spikelets appressed to the panicle branches, with 10-22 florets each  Eragrostis atrovirens

11 Spikelets erect on panicle branches, with 3-10 florets each  Eragrostis curvula

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

12 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  Eragrostis hirsuta

12 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  Eragrostis lugens

9 Stamens 2.

13 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.

14 Spikelets with widely spreading pedicels, the lower pedicels all generally longer than the spikelets; disarticulation of the lemmas only, the paleas persistent  Eragrostis elliottii

14 Spikelets with appressed pedicels, lower pedicels of each branch shorter than the spikelets; disarticulation usually of the whole floret  Eragrostis refracta

13 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.

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

15 Spikelets (0.7-) 1.3-2.4 mm wide; upper glumes 1.4-2.2 mm long; [non-native].

16 Panicles 15-30 cm long; leaf blades (8-) 12-40 cm long, 2-5 mm wide; [SC s. to FL and w. to LA]  Eragrostis bahiensis

16 Panicles 2-12 cm long; leaf blades 4-8 (-18) cm long, 1-2 mm wide; [primarily s. FL]  Eragrostis scaligera

1 Plants cespitose, geniculate or mat-forming annuals, lacking innovations or buds in the lower sheaths.

17 Paleas prominently ciliate-pectinate on the keels, the hairs 0.1-0.8 mm long.

18 Panicles contracted, narrow, spike-like, usually <1.5 cm wide  Eragrostis ciliaris var. ciliaris

18 Panicles open, cylindrical to narrowly ovate, usually 1-8 cm wide.

19 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  Eragrostis amabilis

19 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  Eragrostis cumingii

17 Paleas smooth to scaberulous on the keels, the hairs (if present) <0.1 mm long.

20 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.

21 Hermaphroditic; spikelets bisexual; anthers 2, each 0.2-0.3 mm long  Eragrostis hypnoides

21 Dioecious; spikelets unisexual; anthers 3, each 1.4-2.2 mm long  Eragrostis reptans

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

22 Ligules membranous, glabrous  Eragrostis japonica

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

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

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

25 Spikelets ovate to oblong in outline, >1.4 mm wide; lower glume 1.2-2.3 mm long  Eragrostis mexicana ssp. mexicana

25 Spikelets linear to linear-lanceolate, <1.5 mm wide; lower glume 0.7-1.7 mm long  Eragrostis mexicana ssp. virescens

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

26 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  Eragrostis capillaris

26 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  Eragrostis frankii

23 Caryopsis not grooved on the adaxial surface.

27 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.

28 Spikelets (1.7-) 2-4 mm long, 3-6-flowered  Eragrostis frankii

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

29 Spikelets 0.6-1.3 mm wide; pedicels 1-10 mm long, flexuous and delicate, appressed or spreading  Eragrostis pilosa var. pilosa

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

30 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  Eragrostis cilianensis

30 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.

31 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  Eragrostis barrelieri

31 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  Eragrostis minor

27 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.

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

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

33 Spikelets 3-6-flowered  Eragrostis frankii

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

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

35 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  Eragrostis cumingii

35 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  Eragrostis gangetica

34 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.

36 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  Eragrostis pilosa var. pilosa

36 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.

37 Anthers 0.5-0.7 mm long; [endemic to s. FL]  Eragrostis tracyi

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

38 Pedicels widely spreading  Eragrostis pectinacea var. miserrima

38 Pedicels appressed or rarely diverging up to 20 degrees from the branches  Eragrostis pectinacea var. pectinacea