52 GRAMLNLAE. 



I. Spike lets in a dense spike, 1 or both outer glumes 



ciliate Netjrachne 8. 



I. Spikelets in pairs, one sessile, the other pedicellate. 



Spikelets silky Imperata 1. 



Spikelets glabrous Rottboellia 3. 



D. Flowering glume awned ; 3rd glume minute ; spikelets 

 arranged in spikes. 

 J. Spikelets in pairs or triplets, 1 sessile and 1 or 2 pedicel- 

 late. 



Both spikelets fertile Pollinia 2. 



Sessile spikelet only fertile ; flowering glume awnlike . . Andropogon 4. 

 J. Spikelets in triplets, surrounded by 4 sterile spikelets. 

 Triplet disarticulating below callus, leaving the 4 



sterile spikelets Themeda 5. 



Triplet falling off with the 4 sterile spikelets Iseilema 6. 



2. Pedicels not articulate below the 2 outer glumes, but the axis (rhachilla) of the spikelet 

 usually articulate above the outer glumes and below the flowering glumes, so that, when the 

 latter have fallen, the outer glumes still remain at the summit of the pedicel. 



K. Spikelets with I fertile flower. 



L. Flowering glumes entire or slightly bilobed, awnless or 

 with a single unbranched awn. 

 M. Spikelets in solitary terminal spikes. 



Spikelets solitary in alternate notches Lepturus 74 . 



Spikelets 3 together Hordeum 76. 



M. Spikelets in digitate spikes. 



Flowering glume awned Chloris 69. 



Flowering glume awnless Cynodon 68. 



M. Spikelets arranged in a panicle. 

 N. Outer glumes 2. 



0. Flowering glume awnless ; perennials. 

 P. Outer glumes longer than flowers. 



Panicle spikelike Ammophtla 36. 



Panicle loose (partly) Agrostis 32. 



P. Outer glumes not longer than flowers Sporobolus 30. 



0. Flowering glume usually with a twisted awn ; 



panicle loose or dense : perennials 



Q. Awn dorsal near middle or base of glume. 



Callus with a tuft of hairs Calamagrostis 33. 



Callus glabrous or almost so (partly) Agrostis 32. 



Q. Awn dorsal, near summit of glume Dichelachne 35. 



Q. Awn terminal, long ; panicle loose Stipa 26. 



0. Flowering glume with a short straight awn. 



Awn terminal ; panicle loose ; perennial Oryzopsis 27. 



Awn dorsal; panicle spikelike; annual Gastridtum 34. 



0. Flowering and outer glumes awned ; panicle dense, 



ovoid Lagurus 38. 



N. Outer glumes 4. 



R. Two lowest glumes shorter than flower. 



Stamens 4-6 Ehrharta 20. 



Stamens 4 Microlaena 21. 



R. Two lowest glumes longer than flower ; panicle 

 dense. 



3rd and 4th glumes awned Anthoxanthum 23. 



3rd and 4th glumes awnless, minute Phalaris 22. 



L. Flowering glume with a 3 -branched awn Aristida 25. 



L. Flowering glume 3-9-lobed ; panicle usually dense. 

 S. Flowering glume 3-lobed. 



All 3 lobes ending in awns Amphipogon 24. 



Central lobe with a long awn Echinopogon 28. 



S. Flowering glume 5-lobed, the central lobe conspicuously 



awned Pentapogon 37. 



K. Spikelets with 1 fertile flower and 1 male or empty flower 

 above it. 

 T. Lower flower bisexual ; flowering glume rather thin ; 

 panicle narrow. 

 Flowering glume with 1 slender awn or awnless. 



Upper flower male ; spikelets all alike Holcus 43. 



Upper flower empty ; many spikelets barren Lamarckia 53. 



Flowering glume with 9 stiff plumose awns Pappophorum 47. 



