1. Plants prostrate basally, rooting at lower nodes; nodes of culm bearded (very rarely glabrate).
1. Plants ± erect or spreading from the base, not rooting at the nodes; nodes of culm glabrous.
2. Margins (often inrolled) of leaves and also (usually at least sparsely) pedicels and keels of lemmas and glumes ± glandular-warty.
3. Well-developed spikelets (2.2–) 2.5–3.5 (–4) mm wide; larger glume 1.7–2.5 mm long; sheaths essentially glabrous except at summit.
3. Well-developed spikelets 1.5–2 (–2.2) mm wide; larger glume 1–1.5 (–1.8) mm long; sheaths sparsely pilose.
2. Margins of leaves, pedicels, and keels of lemmas and glumes not glandular-warty.
4. Spikelets reddish to purplish (except in E. curvula); plants perennial, with hard knotty base; lowest panicle branches usually with a long-pilose white to yellowish or red pulvinus in the axil.
5. Spikelets appressed, longer than their pedicels, dull gray; widest leaves 1–3 mm wide, involute, especially above the middle.
5. Spikelets spreading, mostly shorter than their pedicels, reddish-purple tinged; widest leaves 3–8 mm wide, ± flat.
6. Larger glumes 1.4–2.3 mm long; lower panicle branches reflexed at maturity.
6. Larger glumes 2.3–4.5 mm long; lower panicle branches ascending at maturity.
4. Spikelets greenish gray to dark lead-colored (occasionally with purplish flush besides); plants annual, with relatively soft base; lowest panicle branches with pulvinus glabrous to sparsely pilose (or obscure or absent).
7. Larger spikelets mostly 6–11 (–15)-flowered, usually on ± appressed pedicels (though panicle branches may be widely spreading); lowest lemma ca. 1.4–2 mm long; lateral nerves of lemma distinct (in E. pectinacea).
8. Lateral nerves of lemma distinct, at least on lower half; larger mature spikelets (1.3–) 1.5–2 mm wide; axils of panicle glabrous or rarely the lowermost with a few hairs; panicle branches usually alternate or subopposite at lowest two nodes of inflorescence.
8. Lateral nerves of lemma usually obscure; larger mature spikelets ca. 1–1.4 mm wide; axils of lower primary branches of panicle sparsely pilose; panicle branches whorled or clustered at one of the two lowest nodes of inflorescence.
E. pilosa (in part)
7. Larger spikelets mostly 2–4 (–6)-flowered, on spreading pedicels; lowest lemma ca. 1.2–1.4 (–1.6 or very rarely 1.9) mm long; lateral nerves of lemma obscure.
9. Sheaths pilose; grain with a groove the length of one edge; length of culm below lowest branch of terminal panicle less than the height of the panicle.
9. Sheaths essentially glabrous except at summit; grain not grooved; length of culm below lowest branch of terminal panicle usually more than the panicle.
10. Axils glabrous; tip of second glume ± opposite tip of lowest lemma.
10. Axils of at least the lower primary branches of panicle sparsely long-pilose; tip of second glume usually much shorter than the lowest lemma (across from it).
E. pilosa (in part)