Jones: Flora of Illinois, 22. Gramineae 47 



Tribe 2. Festuceae. — Fescue Tribe 



I. Plants 2-4 m. tall; rachilla plumose; panicles large 11. Phragmites 



I. Plants less tall; rachilla not plumose. 

 2. Lemmas prominently 3-nerved. 



3. Lemmas more or less villous on the nerves. 



4. Stem-nodes glabrous; palet not ciliate 13. Trtodta 



4. Stem-nodes pubescent; palet conspicuously ciliate 14. Triplasis 



3. Lemmas glabrous, or merely scabrous on the nerves. 



5. Lemmas less than 5 mm. long 7. Eragrostis 



5. Lemmas about 8 mm. long; the upper 2-4 lemmas empty 8. Diarrhena 



2. Lemmas 5-many-nerved, (the nerves sometimes indistinct). 



6. Spikelets with sterile lemmas above or below the fertile florets. 



7. Sterile lemmas above the fertile florets 12. Melica 



7. Sterile lemmas below the fertile florets 9. Uniola 



6. Spikelets without sterile lemmas. 



8. Lemmas awned. 



9. Lemmas bifid at apex, awned just below the apex or behind the teeth 



- 2. Bromus 



9. Lemmas entire, with an apical point or awn.. 3. Fesluca 



8. Lemmas awnless. 



10. Spikelets nodding, as broad as long, on capillary pedicels in open panicles; 



lemmas papery, imbricated, scarious-margined, cordate at the base, the 



apex obtuse or acutish 6. Briza 



10. Spikelets not as above in all respects. 



1 I . Spikelets strongly flattened, crowded in 1 -sided clusters at the ends of 



long branches ; keels of the glumes and lemmas hispid-ciliale 



:- 10. Dacl}}lis 



11. Spikelets neither strongly flattened, nor in 1 -sided clusters. 



12. Lemmas with cobwebby hairs at base 5. Poa 



12. Lemmas without cobwebby hairs. 



13. Nerves of the lemma parallel and prominent; lemma obtuse, 

 scarious at apex; tall perennials with flat leaves. ...4. Clvceria 



13. Nerves of the lemma converging at the apex (sometimes indis- 

 tinct). 



14. Lemmas 8-11 mm. long; spikelets large 2. Bromus 



14. Lemmas less than 8 mm. long. 



15. Lemmas keeled on the back, the apex obtuse or acute 



5. Poa 



15. Lemmas convex on the back or subcarinate, acute or awn- 

 tipped (obtusish in F. obtusa) 3. Fesluca 



Tribe 3. Horde ae. — Barley Tribe 



1. Spikelets solitary at each joint of the rachis. 



2. Spikelets placed edgewise to the rachis; first glume of the lateral spikelets absent 



21 . Lolium 



2. Spikelets placed flatwise to the rachis; glumes 2. 



3. Glumes 1 -nerved; spikelets with 2 perfect flowers 17. Secale 



3. Glumes 3-several-nerved. 



4. Glumes lanceolate or linear 15. Agrop^ron 



4. Glumes ovate 16. Triticum 



1. Spikelets 2-6 at each joint of the rachis. 



5. Spikelets 3 at each joint, 1 -flowered, the lateral pair usually aborted; glumes awn- 

 like 20. Hordeum 



