TRIANDRIA. 11 



18. SCIRPUS. Corolla none ; glumes imbricated all round, uni- 



form, concave, expanded; style simple at the base, deci- 

 duous. 



19. ELEOCHARIS. Corolla none; glumes imbricated all round, 



uniform, expanded; seed crowned and articulated with 

 the dilated hardened base of the style. 



20. ERIOPHORUM. Coro//anone; glumes imbricated all round, 



uniform, expanded; seed subtended by numerous very 

 long hairs. 



21. NARDUS. Corolla of 2 valves ; calyx none. 



II. DIGYNIA. 



(TRUE GRASSES.) 



* Flowers dispersed. Calyx of 2 or 3 valves, with a solitary floret. 



24. ALOPECURUS. Calyx of 2 valves ; corolla of 1 valve, simple 



at the summit, awned at the base ; styles combined. 



23. PHLEUM. Calyx of 2 close parallel pointed valves, conceal- 

 ing the corolla of 2 awnless valves ; seed loose. 



22. PHALARIS. Calyx of 2 close parallel valves, concealing the 



double corolla of 3 or 4 valves, 2 innermost downy, sub- 

 sequently hardened, investing the seed. 



25. AGROSTIS. Calyx of 2 acute valves shorter than the corolla, 



which is membranous, tufted with hairs at the base, un- 

 changed ; seed loose. 



* * Flowers dispersed. Calyx of 2 valves containing 2 or 3 florets. 



2G. AIRA. Florets 2, without any intermediate rudiment ; seed 

 loose ; corolla unchanged. 



28. MEL ic A. Florets 1 or 2, with the rudiments of 1 or 2 inter- 

 mediate ones ; seed coated with the hardened corolla* 



27. HOLCUS. One floret barren ; corolla awned ; seed coated with 

 the hardened corolla ; calyx keeled. 



