The Natural History of Bi-itisli Grasses. 171 



C. — Stamens, 3. Styles, 2. 



* Spikelets single flowered. 

 t Floivers sjpiked. 



4. Leersia — glumes absent. 



5. Alopecurus — spicate, glumes connected at the base, spike compact. 



6. Phleum — spicate, glumes distinct, spike compact. 



7. Ammopbila — spicate, glumes pointed, with a tuft of hairs at the base, 



spike comijact. 



8. Lagurus — spicate, glumes with long bristly 'points, spike short and 



compact. 



9. Phalaris — spicate, glumes broad, glistening seeds, smooth, spike less 



compact. 



10. Gastridiurii — spicate, glumes swelling at the base, spike less compact. 



11. Polyjjogon — spicate, outer glutne awned, spike less compact. 



ft FloAvers paniculate, more or less lax. 



12. Milium — panicle spreading, glumes herbaceous. 



13. Sti^m — panicle erect, glumes coming out to a fine point, inner glumel 



with an uvea ten times the length of the flower. 



14. Calamagrost is — panicle loose, glumes surrounded by silky hairs. 



15. Agrostis — jianicle loose, glumes lancet-shaped, nearly equal. 



ttt Flowers spicate, arranged on two sides. 

 IG. Eottbolia — spikclcts alternate, glumes equal. 



tttt Spikelets arranged unilaterally. 



17. Spartina — spikelets unilateral, glumes unequal. 



18. Cynodon — spikelets in alternate pairs on one side, glumes very nnequal. 



19. Digitaria — spikes branched, si^ikelets alternate on one side, glumes very 



unequal. 



** Spikelets with one or two perfect florets, sometimes with one or additional 



florets, which are imperfect. 



tt Fertile flowers, one ; imperfect flowers, one or two. 



20. Setaria — jianicle spicate, flowers surrounded by bristles. 



21. Panicum — panicle spicate, spike-branched glumels, with short hairs. 



22. Molinia — panicle contracted but not spicate, glumes acute. 



23. Melica — panicle lax, glumes rounded. 



24. Catabrosa — panicle spreading, glumes obtuse. 



25. Aira — panicle spreading, glumes unequal in size. 



26. Triodia — panicle of few locustcp, which are large and tumid. 



27. llolcus — panicle lax, florets soft, with do\vny hairs. 



28. Arrhenatherum — panicle lax, glumes and glumels with bifid or notched 



points. 



29. Sesleria — panicle spicate, glumes with trifid, glumels with bifid points. 



30. Cynosurus — panicle spicate,flowers hidden in a comb-like shield, involucre 



of botanists. 



*** Spikelets (locnstce), with three or more perfect flowers, 

 t Spikelets forming bilateral spikes. 



31. Elymiis — spikelets (?.) in twos or threes, both valves of the glume on one 



side of the spikelet. 



32. Jlordeum — spikelets (/.) in threes, of which only the central one is perfect. 



33. Triticum — spikelets (/.) alternate on the central axis {nickis), glumes 



transverse to it. 



34. Brachypodium — spikelets (7.) alternate on the central axis (rachis), 



glumes transverse to it. 



