io8 Memoirs L>cniicc P. Bishop Mitscinn 



Lemmas lunger than l)i"oa(I. the margins clasping the palea : Horets not horizontally spreading. 

 Lemmas keeled on the back. 



Spikelets strongly compressed, crowded in one-sided clusters at the ends of the 



stiff, naked ijanicle brandies 8. D.\ctylis (p. 137 I 



Spikelets not strongly compressed, not crowded in one-sided clusters. 



Lemmas awned from a minutely bifid apex (awnless or nearly so in Broiiuis 



iiiiioloidcs) : spikelets large 2. Bromus (p. hi) 



Lemmas awnless; spikelets small 5. Po.\ (j). 117) 



Lemmas founded on the back, sometimes slightl)' keeled toward the summit. 



Xerves of the lemma parallel, not converging at the summit or but slightly so ; 



lemmas awnless. mostly obtuse 4. P.\nicul.\ria (p. 116) 



Xerves of the lemma converging at the summit ; lemmas awned or pointed. 



Lemmas entire, awned from the tip or pointed 3. Festuc.v (p. 115) 



Lemmas awned or awn-tipjied tnim a nnnutely bifid apex. .2. Bromus (p. iii ) 



HORDEAE. 



Spikelets more tlian i at each node of the rachis 9. HordEUM (p. 139) 



Spikelets solitary at each node of the rachis. 



Spikelets several-flowered in flat spikes 10. Lolium (p. 139) 



Spikelets i-flowered in cylindric spikes 11. Lepturus (p. 141) 



AVENEAE. 



Florets 2. one perfect, the other staminate. 



Lower floret staminate. the awn twisted, geniculate. exserted..i4. Arrhen'athervm (p. 143) 



Lower floret perfect, awnless: awn of upper floret hooked 17. Xotholcus (p. 147) 



Florets 2 or more, all alike except the reduced upper ones. 



Spikelets large, the glumes over i cm. long 13. AvEx.v (p. 142) 



Spikelets less than i cm. long. 



Lemmas keeled, bidentate ; awn arising from above the middle (sometimes wanting.) 



12. Trisetu.m ( p. 141 ; 



Lemmas convex ; awn from below the middle. 



Rachilla prolonged behind the upper floret ; lemmas truncate and erose-dentate 



at summit: plants perennial 15. Aira (p. 143) 



Rachilla not prolonged : lemmas tapering into 2 slender teeth ; plants annual 



16. .AsPRis (p. 145) 



AGROSTIDEAE. 



Rachilla articulate below the glumes, these falling with the spikelet : glumes awned : lemmas 

 awned from the tip. 



Spikelets pilose at base, in narrow loose simple ])anicles 20. Garnotia (p. 1551 



Spikelets not pilose at base, in dense spikelike panicles 21. Polvpogon (p. 155) 



Rachilla articulate above the glumes. 



Glumes not longer than the lemma, unequal: spikelets awnless it,. Sporobolus (p. 157) 



Glumes longer than the lemma, alx)ut equal. 



Glumes saccate at base; lemma long-awned ; inflorescence contracted, shining 



22. Gastridium ( p. 157) 



Glumes not saccate at base. 



Florets bearing at base a tuft of hairs 18. C.\L a.m.vgrostis (p. 147) 



Florets without hair> at base 19. Agrostis (p. 149) 



CHLORIDEAE. 



Spikelets with more than i perfect floret. 



Rachis not prolonged 24. ElEusine (p. 159) 



Rachis of spike extending beyond the spikelets 25. Dactvloctexium (p. 161) 



[ 10] 



