Brachiaria Griseb., s.l.

Key to the species of Brachiaria s.l., Echinochloa p.p., Moorochloa, and Urochloa p.p. in Madagascar

1. Spikelets ≥ 3 mm long................................................. 2

1a. Spikelets <3 mm long............................................... 17

2. Spikelets in a dense and tidy imbricate arrangement of evenly sized racemes; rhachis narrowly winged to broad and foliaceous, (0.5–) 0.8–3.5 mm wide....................... 3

2a. Spikelets not overlapping or overlapping untidily, racemes usually decreasing in length towards apex of synflorescence; rhachis narrow or triquetrous, <0.8 mm wide (rarely narrowly winged up to 1 mm wide)................ 10

3. Lower glume turned away from rhachis, turned towards viewer and therefore visible on majority of spikelets; upper lemma rugulose, with a mucro 0.3–1.2 mm long.......... 4

3a. Lower glume turned towards rhachis, turned away from viewer and not immediately visible on majority of spikelets; upper lemma smooth to rugulose, without or with a minute mucro.............................................................. 5

4. Lower glume ¼–⅓ as long as spikelet; spikelets acute, usually without a setose fringe... 26. Urochloa panicoides

4a. Lower glume ⅔–¾ as long as spikelet; spikelets acuminate, usually with a prominent setose fringe....................................................................... 31. Urochloa trichopus

5. Spikelets 3–4 mm long................................................ 6

5a. Spikelets 4–6 mm long............................................... 8

6. Rhachis margins with yellow bulbous based trichomes; lower glume ⅔–¾ as long as spikelet...................................................................................... 23. Urochloa jubata

6a. Rhachis margins scaberulous or with translucent trichomes; lower glume ⅓–½ as long as spikelet............. 7

7. Spikelets 2.5 –3.7 mm long; lower glume 5 – 7-veined; mostly prostrate plants of low elevations............................................................................ 19. Urochloa distachyos

7a. Spikelets 3.5–4 mm long; lower glume 3-veined; mostly erect plants of High Plateau.......... 16. Urochloa arrecta

8. Rhachis scaberulous; spikelets not obviously plump, acute................................................ 27. Urochloa plantaginea

8a. Rhachis ciliate; spikelets plump and subacute............. 9

9. Rhachis 1–1.5 mm wide; upper glume and lower lemma cartilaginous, dully shining........ 17. Urochloa brizantha

9a. Rhachis 2–3.5 mm wide; upper glume and lower lemma membranous, not shining............... 20. Urochloa eminii

10. Spikelets with a prominent ciliate rim ⅔ from base, with dense white trichomes 1–2 mm long.............................................................................. 9. Brachiaria subrostrata

10a. Spikelets with a no ciliate rim, glabrous to evenly pilose, with trichomes <1 mm long...................................... 11

11. Lower glume ⅔ to as long as spikelet........................ 12

11a. Lower glume up to ½ as long as spikelet................... 14

12. Spikelets dorsally compressed; glumes acuminate to mucronate.................................... 21. Urochloa glumaris

12a. Spikelets laterally compressed; glumes pinched at apices................................................................................... 13

13. Leaf blades linear or rolled, 3–6 mm wide; plants with no smell.................................... 1. Brachiaria antsirabensis

13a. Leaf blades lanceolate, 12–20 mm wide; plants scented.................................................... 6. Brachiaria fragrans

14. Spikelets oblong; upper lemma smooth and shiny............................................... 10. Brachiaria tsiafajavonensis

14a. Spikelets ellipsoid; upper lemma rugulose to rugose... 15

15. Stoloniferous perennials; leaf blades linear; spikelets arranged in several untidy rows..... 24. Urochloa mutica

15a. Loosely tufted annuals; leaf blades lanceolate; spikelets paired........................................................................ 16

16. At least some pedicels longer than spikelets........................................................................... 18. Urochloa deflexa

16a. All pedicels shorter than spikelets......................................................................................... 29. Urochloa ramosa

17. Spikelets ≤ 2 mm long............................................... 18

17a. Spikelets> 2 mm long............................................... 24

18. Spikelets on a single raceme not overlapping, with gaps between..................................................................... 19

18a. Spikelets on a single raceme imbricate or overlapping, with no gaps between most spikelets......................... 21

19. Lower glume absent or up to ⅓ of spikelet length, with no veins; leaf blades thickly chartaceous; spikelets single........................................................ 11. Brachiaria umbellata

19a. Lower glume ½–⅔ as long as spikelet, 3-veined; leaf blades membranous to chartaceous; spikelets paired............. 20

20. Spikelets apically rounded, whiteish, usually> 15 per inflorescence; leaf blades 1–7 × 0.3–1 cm............................................................................ 2. Brachiaria bemarivensis

20a. Spikelets apically acute, green, ≤ 15 per inflorescence; leaf blades 0.5–1.5 × 0.1–0.45 cm... 5. Brachiaria epacridifolia

21. Mat-forming plants not rising> 5 cm above ground level; ligule absent............................... 14. Echinochloa serpens

21a. Plant with erect flowering culms; ligule present........ 22

22. Leaf blades linear; loosely tufted annuals with no stolons; spikelets tidily imbricate on evenly sized racemes....................................................... 15. Moorochloa eruciformis

22a. Leaf blades lanceolate to elliptic or ovate; stoloniferous annuals or perennials; spikelets untidily overlapping on racemes, these decreasing in length going up synflorescence.......................................................................... 23

23. Inflorescence 5–35 cm long; spikelets elliptic to oblong, apically rounded; upper lemma smooth with no mucro................................................. 3. Brachiaria comorensis

23a. Inflorescence 3–5 cm long; spikelets ovate, apically acute; upper lemma finely rugulose, mucronate............................................................................... 30. Urochloa reptans

24. Spikelets densely covered with white to pink trichomes, with short white trichomes in lower part and dense white to pink trichomes c. 2 mm long in upper third; lower lemma grooved and mucronate.... 8. Brachiaria perrieri

24a. Spikelets glabrous or evenly pubescent; lower lemma not grooved or mucronate................................................ 25

25. Lower glume ⅔–¾ as long as spikelet....................... 26

25a. Lower glume minute or up to ⅔ as long as spikelet.. 29

26. Rhachis margins ciliate with yellow bulbous-based trichomes........................................... 23. Urochloa jubata

26a. Rhachis margins scaberulous or with linear translucent trichomes................................................................... 27

27. Spikelets dorsally compressed; ligule absent............................................................... 13. Echinochloa leandriana

27a. Spikelets laterally compressed; ligule a truncate membrane......................................................................... 28

28. Leaf blades linear, 3–7 cm long................................................................................... 1. Brachiaria antsirabensis

28a. Leaf blades lanceolate, 0.8–3 cm long............................................................................. 4. Brachiaria dimorpha

29. Spikelets within a single raceme not overlapping...... 30

29a. Spikelets within a single raceme overlapping or imbricate................................................................................... 34

30. Culms woody; plants resembling a miniature bamboo................................................. 7. Brachiaria fruticulosa

30a. Culms herbaceous; plants a mat forming, stoloniferous, or annual grasses........................................................ 31

31. Spikelets plump, apiculate; upper lemma rugose.................................................................. 29. Urochloa ramosa

31a. Spikelets not obviously plump, apically rounded to subacute; upper lemma usually smooth, sometimes finely rugulose..................................................................... 32

32. Leaf blades membranous; lower glume ½–⅔ as long as spikelet................................ 2. Brachiaria bemarivensis

32a. Leaf blades chartaceous; lower glume ¼–⅓ as long as spikelet...................................................................... 33

33. Leaf blades 1–5 mm wide; open and partly closed canopy habitats in southern Madagascar <800 m elevation..................................................... 22. Urochloa humbertiana

33a. Leaf blades 6–12 mm wide; forest shade in central, northern, and eastern Madagascar at 650–2300 m elevation........................................... 10. Brachiaria tsiafajavonensis

34. Inflorescence capitate, with up to 15(– 30) spikelets on each culm............................. 12. Echinochloa hubbardii

34a. Inflorescence racemose, with> 15 spikelets on each culm................................................................................... 35

35. Racemes 1 –2; plants sprawling branched at every node........................................ 28. Urochloa pseudodichotoma

35a. Racemes> 2; plants sprawling to erect, not branching at every node................................................................. 36

36. Plants annual, with no stolons................................... 37

36a. Plants perennial, stoloniferous or rarely annuals........ 38

37. Spikelets subsessile and tidily imbricate on appressed racemes................................ 15. Moorochloa eruciformis

37a. Spikelets on pedicels of uneven length, partly overlapping, racemes divergent.......................... 29. Urochloa ramosa

38. Racemes 5–20; spikelets in several untidy rows.................................................................... 24. Urochloa mutica

38a. Racemes 2–7; spikelets in 2 rows or not arranged in rows................................................................................... 39

39. Leaf blades 6–12 mm wide; spikelets oblong; species of forests.......................... 10. Brachiaria tsiafajavonensis

39a. Leaf blades 3–7 mm wide; spikelets ellipsoid; species of open areas.................................................................. 40

40. Spikelets neatly imbricate.......... 19. Urochloa distachyos 40a. Spikelets overlapping untidily.......... 25. Urochloa nana