55© GRAMfNE^ 



14. PoLYPOGON. — Panicle spike-like ; glumes awned. 



15. Calamagrostis. — Rachilla with long, silky hairs; flowering 

 glume awned. 



■^* Rachilla produced beyond flowering glume 



16. Gastridium. — Panicle spike-like; outer glumes awnless ; 

 flowering glume minute, 4-toothed. 



17. Apera. — Panicle loose; flowering glume slightly 2-fid, with 

 a long, slender awn. 



18. Ammophila. — Panicle spike-like; spikelets large; rachilla 

 long, silky ; flowering glume minutely awned. 



19. Lagurus. — Panicle spike-like, ovate; outer glumes ending 

 in a long, fringed bristle ; flowering glume 3-awned. 



Tribe 5. AvenecR. — Spikelets in panicles, 2 — ^-flowered ; rachilla 

 generally produced beyond the flowering glume ; glumes 4 or more, 

 2 lowest empty, equalling or overtopping the flowers ; flowering 

 glumes with twisted dorsal awns 



20. Air A. — Panicle loose ; rachilla not produced ; awn dorsal, 

 generally bent ; ovary glabrous. 



21. CoRYNEPHORUS. — Flowers 2, perfect; awn jointed in the 

 middle, with a club-shaped tip. 



22. HoLCUS. — Flowers 2, lower perfect, awnless, upper stami- 

 nate, awned. 



23. Trisetum. — Flowers 2 — 6 ; flowering glume with 2 acute 

 teeth and a bent, twisted dorsal awjt ; ovary smooth. 



24. AvENA. — Flowers 2 or more ; flowering glume with 2 points 

 and a bent, twisted, terminal awn ; ovary hairy. 



25. Arrhenatherum. — Flowers 2, lower staminate, with long, 

 basal, bent, twisted awn, upper perfect^ awnless, or with short, 

 straight awn. 



Tribe 6. Chloridece. — Spikelets in 2 rows on a flattened rachis, 

 forming a i-sided spike or raceme, laterally compressed, i-flowered 



26. Cynodon. — Spikes spreading, digitate; glumes awnless. 



Tribe 7. Festucece. — Rachilla usually produced ; glumes 6 or more, 

 the 2 lowest empty ; own terminal or absent 



27. Sieglingia. — Spikelets seldom more than 5 or 6, in a race- 

 mose panicle, awnless, 2 — 4-fiowered ; flowering glume with 3 

 minute teeth at the top. 



28. Phragmites. — Spikelets in a spreading panicle, i — 6- 

 flowered, awnless ; rachilla bearded with long, silky hairs. 



