| |
| | 2. Lemma awned, awn 1–3 cm, lemma 2.5–6 mm |
| |
| | 3. Lemma generally 4.5–6 mm; inflorescence branches closely appressed, < 1.5 cm wide; glumes generally 1–2 mm |
| M. appressa |
| | 3' Lemma generally 2.5–4.5 mm; inflorescence branches spreading to ascending, 1–5 cm wide; glumes generally < 1 mm |
| 2 M. microsperma |
| | 2' Lemma abruptly pointed, point < 1 mm, or awn 0; lemma < 2.5 mm |
| |
| | 4. Inflorescence narrow, < 1 cm wide; branches closely appressed; stems often rooting at lower nodes |
| 2 M. filiformis |
| | 4' Inflorescence open, 1.5–8 cm wide; branches reflexed to ascending; stems not rooting at lower nodes |
| |
| | 5. Inflorescence branches stiffly reflexed ± 90° from axis; glumes glabrous; ligule teeth 2, 1 on each side |
| M. fragilis |
| | 5' Inflorescence branches ascending < 80° from axis; glume tip short-hairy; ligule truncate to obtuse, irregularly short-toothed |
| M. minutissima |
| |
| | 6. Lemma awn 0 or short-pointed, point < 1 mm |
| |
| | 7. Inflorescence 5–14 cm wide, open, branches spreading |
| M. asperifolia |
| | 7' Inflorescence < 4 cm wide, narrow, branches ascending to appressed |
| |
| | 8. Rhizomes creeping, ± scaly; stems ± decumbent |
| |
| | 9. Glumes 2.5–4 mm, ± = lemma; lower half lemma short-soft-hairy |
| 2 M. californica |
| | 9' Glumes 0.5–1.8 mm, ± 1/2 lemma length; lemma glabrous to ± scabrous |
| |
| | 10. Ligule generally 1–2.5 mm; inflorescence axis generally obscured by branches, spikelets |
| M. richardsonis |
| | 10' Ligule generally < 1 mm; inflorescence axis generally visible between branches |
| M. utilis |
| | 8' Rhizomes 0; stems clumped or decumbent and ± rooting at the nodes |
| |
| | 11. Blade < 4 cm; lemma generally < 2 mm; stems generally < 3 dm |
| |
| | 12. Lemma short-awned, awn < 1 mm; glumes 0.5–1.2 mm; ligule 1–2.5 mm, obtuse to acute |
| 2 M. filiformis |
| | 12' Lemma awn 1.5–5 mm; glumes < 0.5 mm; ligule < 0.5 mm, truncate |
| 2 M. schreberi |
| | 11' Blade > 5 cm; lemma generally > 2.5 mm; stems 2–15 dm |
| |
| | 13. Inflorescence < 15 cm, 1.5–4 cm wide; branches loosely flowered |
| M. jonesii |
| | 13' Inflorescence 15–60 cm, < 1.2 cm wide; branches densely flowered |
| M. rigens |
| |
| | 14. Inflorescence open, 6–15 cm wide, branches spreading |
| M. porteri |
| | 14' Inflorescence < 5 cm wide, branches ascending to appressed |
| |
| | 15. Glumes 1 or 2, generally < 0.5 mm, vein 0 |
| 2 M. schreberi |
| | 15' Glumes 2, generally > 0.5 mm, vein evident |
| |
| | 16. Rhizome generally scaly, creeping |
| |
| | 17. Blade generally rolled, < 2 mm wide; anther purple, 1.5–3 mm |
| |
| | 18. Lemma, palea short-soft-hairy on lower half; stems loosely clumped, decumbent |
| 2 M. arsenei |
| | 18' Lemma base sparsely short-hairy; palea glabrous to ± scabrous; stems erect, ± rooting at lower nodes |
| 2 M. pauciflora |
| | 17' Blade generally flat, > 2 mm wide; anther yellow, generally < 1.5 mm |
| |
| | 19. Hairs at lemma base 2–3.5 mm |
| M. andina |
| | 19' Hairs at lemma base < 1.5 mm |
| |
| | 20. Lemma awn generally < 2.2 mm; anther 1–1.5 mm |
| 2 M. californica |
| | 20' Lemma awn 2.5–9 mm; anther < 0.5 mm |
| M. mexicana |
| |
| | 21. Upper glume 3-veined, 3-toothed |
| M. montana |
| | 21' Upper glume generally 1-veined, obtuse, acute, or awned |
| |
| | 22. Glumes generally < 1.5 mm, obtuse; cleistogamous spikelets generally present in lowermost stem axils |
| 2 M. microsperma |
| | 22' Glumes generally 1.5–3.5 mm, acute, acuminate, or awned; cleistogamous spikelets 0 |
| |
| | 23. Lemma, palea short-soft-hairy on lower half; stems loosely clumped, decumbent |
| 2 M. arsenei |
| | 23' Lemma base sparsely short-hairy; palea glabrous to ± scabrous; stems erect, ± rooting at lower nodes |
| 2 M. pauciflora
|