Eragrostis

Eragrostis

In this genus, for keying it is important to use mature spikelets. The spikelets continue to grow significantly after emergence of the inflorescence.

A. Rare in our area, E. secundiflora uniquely has second glumes and lemmas > 2.5 mm long.

A. If the dimensions are smaller, proceed with the key:

1. Plants (sheaths, glumes, lemmas) glandular OR with long cilia on the paleas. Inflorescences pencil-shaped or cylindric, usually < 4 cm in diameter…2

1. Plants not glandular, and paleas without long conspicuous marginal cilia (or with tiny cilia < 0.1 mm long). Inflorescences elliptic or ovate, usually (but not always) > 4 cm in diameter…4

2. Leaf sheaths, glumes, and lemmas usually with glands. Spikelets very wide (2-4 mm). Lemmas > 2.5 mm long. Paleas without long comblike cilia…(rare in our area if present at all)

2. Leaf sheaths, glumes and lemmas without glands. Spikelets usually < 2.5 wide; lemmas with long comblike cilia…3

3. Inflorescence narrow, so tightly congested as to hide the branches and pedicels, the shape and size of a pencil to cigar, resembling a furry tail (usually < 2 cm diam.)…

3. Inflorescence usually 1- 5(7) cm wide, cylindric… (usually encountered as a small weed in open, sandy, highly disturbed places)

4. Spikelet 2-4.6 mm X 0.9-2 mm. Lemma 1-1.3 mm; anthers 2…

4. Spikelet dimensions ranging above the above limits. Anthers 2 or 3…5

5. Glumes equal or nearly so, both glumes slightly longer than 1 mm (usually ca. 1.3 mm). Leaf blades 3-8 mm wide. (Note: glumes subequal also in E. atrovirens but its glumes 1.2-1.7 mm and the pulvinus glabrous. Glumes subequal may occur in E. scaligera but this with the inflorescence < 15 cm vs. > 25 cm long)… (Inflorescences often purplish, branch bases with a tuft of hairs, the bases often included in subtending leaf base. Anthers 2)

5. Glumes unequal, or if equal not ca. 1.3 mm long; leaf blades usually < 5 mm wide…6

6. Lower glume 0.3-0.6 mm… (glumes extremely unequal; spikelet usually < 6 mm long; anthers 3)

6. Lower glume > (0.5)0.7 mm…7

7. Pedicels longer than spikelets AND spikelets erect on branches…

7. Pedicels shorter than or equal to spikelets; spikelets usually appressed to branches (spikelets may angle outward from branch but then the pedicels shorter than or equal to the spikelets)…8

8. Main inflorescence branches with long hairs at the bases… $E. refracta$

8. Main inflorescence branches glabrous (or nearly so) at the bases…9

9. Culms > 75 cm tall with the lowest inflorescence branch > 30 cm above the basal leaves. Leaf blades adaxially pilose. Bases of inflorescences branches bare… (anthers 3)

9. Culms usually < 75 cm tall with the lowest inflorescence branches usually < 30 cm above the basal leaves. Leaf blades adaxially glabrous to ciliate. Bases of inflorescence branches often hidden by spikelets, or bare...10 [Eragrostis bahiensis infrequently exceeds 75 cm tall, but differs by having 2 vs. 3 anthers, by ranging to more florets per spikelet (8-30 vs. 10-22 florets), and by ranging to larger leaf blades less likely to be adaxially pilose: 12-40 cm X 2-5 mm vs. 8-20 cm vs. 2-3 mm.]

10. Spikelets overlapping along branches only basally (tip-to-tail, or not overlapping). Inflorescence branches not branched (except occasionally at base). Anthers 3… [E. pectinacea differs from similar E. atrovirens by having adaxial leaf surfaces glabrous as opposed to ciliate. Inflorescence usually as long as its own scape (vs. scape several times longer than the branching portion of the inflorescence). Lemma 0.4-0.6 mm margin-to-keel vs. 0.6-0.8(0.9) mm.]

10. Spikelets overlapping along the inflorescence branches to the spikelet centers or beyond. Anthers 2…11

11. Leaf blades 4-8 cm X 1-2 mm. Lower glume > 1.4 mm. Upper glume (1.6) > 1.7 mm. Inflorescence 5-15 cm X 2-10 cm… (lemma 0.6-0.9 mm margin-to-keel vs. < 0.6 mm in E. pectinacea)

11. Leaf blades 12-40 cm X 2-5 mm. Lower glume < 1.4 mm. Upper glume < 1.7 mm; inflorescence 15-30 cm X 8-17 cm… (E. gangetica similar but with smaller spikelets (2-4.6 mm vs. > 6 mm)

Dimensions below are usual dimensions with extremes omitted.

	Spikelets erect (E) or appressed (A) Pedicel length	Pulvinus P = pilose G = glabrous	Anthers	Lemma length mm	Leaf blades size mm	Spikelet length mm	Florets	Lower glume length mm	Upper glume length mm	Leaf blade hairs	Other
E. pectinacea	A Pedicel 1-7 mm	G mostly	3	1-2.2 Veins not green	2-20 cm X 1-4.5 mm	5-8(11) X 1.2- 2.5	6-22	0.5-1.5	1-1.7	Glabrous	Spikelets loosely imbricate
E. atrovirens	A Pedicel 1-10 mm, shorter than spikelet	G mostly	3	1.3-2 Leathery	8-20 cm X 2-3 mm	5-12 X 1.4-2.4	10-22	1.2-1.4	1.4-1.7	Pilose (vs. similar E. pectinacea)	Can be taller than the other species (exceeding 1 m tall) with inflorescence beginning > 30 cm above base
E. refracta	A Pedicel 0.5-25, shorter than spikelet	P	2	1.4-2.8 Membranous	10-35 cm X 2-5 mm	4-18 X 1.4-3.4	9-30	0.8-2.4	1.5-2.6	May be sparsely pilose
E. bahiensis	A Pedicel 0.6-6 mm, shorter than spikelets	G	2	1.5-2.2 Leathery	12-40 cm X 2-5 mm	6-15 X 1.3 - 2	8 - 30	1-1.4	1.4-1.7	May be ciliate
E. gangetica	A Pedicel 0.3-5 mm, shorter than spikelet	G	2	1-1.3 Veins green	7-17 cm X 1-3 mm	2-4.6 X 0.9-2	5-15	0.4-0.9	1-1.3	May be pubescent	Similar to E. bahiensis but with smaller spikelets
E. elliottii	E Pedicel 10-25 mm, longer than spikelet	P	2	Veins green	6-30 cm X 2-4.5 mm	4-18 X 1.4 - 3	8-15	1.1-3.4	1.6-3.4		E. scaligera has smaller inflorescence
E. pilosa	EA Pedicel 1-10 mm, shorter or longer than spikelet	P	3	1.2-1.8 Membranous Veins inconspicuous	2-20 cm X 1-4.5 mm	3.5-6	5-17	0.3-0.6	1.3	Glabrous	Very unequal glumes Spikelets gray or black
E. spectabilis	EA Pedicel 1.5-17 mm	P	3	1.3-2.5 Leathery	10-32 cm X 3-8 mm	3-7.5 X 1-2	6-12	Glumes equal, usually a little over 1 mm	Glumes equal, usually a little over 1 mm	Pilose or glabrous	Blade to 8 mm wide Glumes nearly equal Inflorescence often purple
E. scaligera	Short pedicels but may angle out	G	2	2-2.5 Leathery	4-8 cm X 1-2 mm	6-15 X 1.6-2.4	10-35	1.4-2.1	1.6-2.2	Pilose or glabrous
E. ciliaris											Distinctive pencil shaped reddish inflorescence <2(4) cm wide; Spikelets < 3.2 mm; palea with long bristles
E. cilianensis											Distinctive congested spikelets 2.5 mm wide. Lemmas 2.5 mm long with long bristles; sheaths with glands on veins
E. amabilis											Distinctive very small species with ciliate palea, and narrow cylindrical yet open inflorescences < 15 cm long and < 7 cm wide; spikelets 1.5-2 with long bristles