Tripogon

K., Thoiba, Abstract, A. K. Pradeep & Roem., Tripogon, 2020, A revision of Tripogon (Poaceae: Chloridoideae) in India, Rheedea 30 (3), pp. 325-378 : 328-332

Key to the species of Tripogon in India

1. Culms thickened below by the persistent leaf sheaths; leaves equitant, rigid and pungent ... ......................................................... T. pungens

1. Culms and leaves not as above ..................... 2

2. Lemmas cleft at the apex into 2 lobes, awned in the cleft ...................................................... 3

2. Lemmas cleft at the apex into 4–6 lobes or not, with or without a definite lobe between each lateral awn and the median awn ................ 14

3. Median awn as long as or longer than the lemmas ........................................................... 4

3. Median awn shorter than the lemma, occasionally almost absent ............................ 8

4. Awns straight or curved, not more than twice as long as the lemmas .................................... 5

4. Awns flexuous, capillary, several times as long as the lemmas ................................ T. capillatus

5. Culms stoloniferous; paleas broadly winged. ........................................................................ 6

5. Culms not as above; paleas narrowly winged ........................................................................ 7

6. Rachilla 1–1.2 mm long; upper glumes awned, 1–1.5 mm long, lemma awns straight at young stage and recurved at maturity ........ T. wightii

6. Rachilla 0.5–1 mm long; upper glumes mucronate, 0.3–0.4 mm long, lemma awns almost straight but slightly bend at maturity. ............................................... T. velliangiriensis

7. Ligules a densely ciliate membrane, often glabrous when dry; spikelets up to 20- flowered; lemma awns flexuous or recurved, lobes awned or not at the apex ....... T. trifidus

7. Ligules a fine glabrous membrane; spikelets up to 8-flowered; lemma awns stout, lobes never awned at the apex....................... T. sivarajanii

8. Tufted perennials with wiry-root forming tufts; leaves glabrous or sparsely hairy; plant greenish (except T. polyanthus ); racemes stout or rigid .......................................................... 9

8. Caespitose perennials with fibrous roots, forming a close turf; leaves covered with a mass of matted hairs; whole plant with a purple tinge; racemes slender ............. T. purpurascens

9. Leaves and culms glaucous; leaves convolute or involute, 4–30 cm long; lower glumes asymmetrical................................................ 10

9. Leaves and culms not glaucous; leaves flat, 30– 70 cm long; lower glumes symmetrical (except T. bimucronatus , T. lisboae )........................... 11

10. Leaves sub-filiform, involute, longer than or equal to racemes; spikelets 7.5–16 mm long, 4–25-flowered; common on barren uplands and old walls ............................ T. jacquemontii

10. Leaves linear, convolute, shorter than racemes; spikelets 2–6.5 cm long, 20–60-flowered; more common in river bed rocks ....... T. polyanthus

11. Ligules absent or indistinct; glumes acuminate, unawned ...................................................... 12

11. Ligules membranous or ciliate; glumes awned; if unawned, then the plants strongly tussock forming with large spikelets on the racemes. ...................................................................... 13

12. Leaves flat or sometimes rolled; ligules absent; upper glumes shortly aristate; palea acute at apex ................................................... T. lisboae

12. Leaves flat; ligules indistinct; upper glumes acute; palea subulate at apex .... T. malabaricus

13. Lower glumes asymmetrical; upper glumes mucronate or shortly awned; paleas bi-mucronate at apex .................. T. bimucronatus

13. Lower glumes symmetrical; upper glumes acuminate; paleas obtuse at apex ... T. vellarianus

14. Lemmas 3-awned with a definite lobe between the awns; anthers 3 ...................................... 15

14. Lemmas 3-awned without definite lobes between the awns; anthers 2 ........................... .......................................... T. mahendragiriensis

15. Lemmas 4-lobed.......................................... 16

15. Lemmas 6-lobed.......................................... 23

16. Median awn shorter than or nearly equal to the lemmas; stout grass ............................... 17

16. Median awn twice as long as the lemma or more; slender grass ...................................... 20

17. Lateral awns of lemma half to median awns. ...................................................................... 18

17. Lateral awns of lemma shorter than to median awns ............................................................. 19

18. Spikelets 5–10 mm long, loosely spaced on the rachis, 4–6-flowered; lower glumes 2.3–3.5 mm long ...................................... T. narayanae

18. Spikelets 10–16 mm long, contracted on the rachis, 10–16-flowered; lower glumes 1–2.7 mm long .................................. T. munnarensis

19. Leaves hairy, spikelets compact; paleas emarginate or bi-lobed with a central notch at apex .............................................. T. bromoides

19. Leaves sparsely hispid; spikelets distant; paleas acute with sub-apical setae at apex................. .................................................... T. idukkianus

20. Culms and awns stout; leaf blades flat-convolute ..................................................... 21

20. Culms and awns flexuous or slender; leaf blades filiform or convolute ................................... 22

21. Rachilla persistent; lower glumes 2 - nerved, 2- keeled; lemma lobes acute to acuminate ........ ................................................. T. karnatakensis

21. Rachilla not persistent; lower glumes 1-nerved, 1-keeled; lemma lobes lanceolate to acuminate ......................................................... T. ravianus

22. Leaf blades densely pilose on both surfaces; racemes with closely imbricate spikelets; lateral awns arising from lemma tooth; anthers 3 .... ....................................................... T. filiformis

22. Leaf blades glabrous or loosely pilose adaxially and glabrous abaxially; racemes with widely spaced spikelets; lateral awns smaller than the median awn, arising free from lemma tooth or from its outer margins; anther 1 ................ ................................................ T. longearistatus

23. Spikelets 3–3.5 mm wide; lower glumes 4–5 mm long; upper glumes 7–9 mm long; anthers 1.3–2 mm long ........................... T. zeylanicus

23. Spikelets 1–2 mm wide; lower glumes 1.8–2.3 mm long; upper glumes 2.3–4 mm long; anthers <1mm long ............................ T. borii