XIV SYNOPSIS OF GENERA. 



Calamagrostts. Panicle loose. Cal. of 2 valves, longer than the two 

 valves of the corolla, p. 297. 



Agrostis. Cal. of 2 acute valves, shorter than the cor. which is membra- 

 nous, tufted with hairs at the base, unchanged. Seed loose, p. 298. 



* * Fl. dispersed. Cal. of 2 valves, containing 2 or 3 florets. 



Catabrosa. Panicle spreading. Cal. of 2 valves, membranaceous, very 

 obtuse, much shorter than the spikelets, 2 or 3-flowered, often with a fourth 

 imperfect floret. Cor. 2-valved, coriaceous, membranous only at the extre- 

 mity, ribbed, truncated, awnless, erose, nearly equal, p. 299. 



Aira. Florets 2, without any intermediate rudiment. Seed loose. Cor. 

 unchanged, p. 299. 



Meltca. Florets 1 or 2, with the rudiments of 1 or 2 intermediate ones. 

 Seed coated with the hardened cor. p. 300. 



Holcus. One floret barren. Cor. awned. Seed coated with the hardened 

 corolla. Cal. keeled, p. 30 J. 



Arrhenatherum. Panicle lax. Cal. of 2 valves, 2-flowered ; lower- 

 most floret with stamens only, and a long twisted awn above the base, upper 

 one perfect, with a short straight bristle below the point, p. 302. 



Sesleria. Florets 2 or 3, all perfect. Outer valve of the cor. toothed ; 

 inner cloven. Seed loose. Styles combined, p. 302. 



* * * Fl. dispersed. Cal. containing many florets. 

 Poa. Cor. awnless, compressed, keeled, ovate, acute. Seed loose, elliptic- 

 oblong, p. 302. 



Triodia. Cor. orbicular, expanded, obscurely ribbed, deeply cloven, with 

 an intermediate point ; both valves concave. Seed loose, depressed, p. 306, 



Briza. Cor. awnless, tumid, expanded, concave, without a keel. Seed 

 depressed, united to the corolla, p. 3 16. 



Dactylis. Cor. awned at the summit, lanceolate, keeled, compressed ; 

 inner valve folded, 2 ribbed. Seed loose, oblong, Cal. compressed, taper- 

 pointed, unequal, p. 307, 



Cynosurus. Cor. awned at the summit, lanceolate, keeled, concave; 

 inner valve flat, 2-ribbed. Seed loose, elliptic-oblong. Cal. awned, equal. 

 Spikelets in pairs ; 1 entirely neuter, p. 3u7. 



Festuca. Cor. awned at the summit, or pointed, keeled, nearly cylin- 

 drical, concave; inner valve flat, 2 ribbed, downy at the ribs. Seed loose, 

 oblong. Cal. concave, acute, very unequal, p. 3U7- 



Bromtjs. Cor. awned at the back, cloven, concave ; inner valve flat, 

 2-ribbed, bristly at the ribs. Seed elliptic-oblong, united to the inner valve. 

 p. 310. 



Avena. Cor. awned at the back, cloven, nearly cylindrical; inner valve 

 flat, ovate. Seed elliptic-oblong, united to the hard outer valve, p. 312. 



Arundo. Cor. surrounded with long permanent hairs. Florets 1 or 

 many. p. 313. 



* * * * Fl. aggregate, on a jointed, or toothed, common stalk, with lateral 

 excavations. 

 Elymus. Cal. of 2 parallel valves, aggregate, with two or more florets. 

 p. 313. 



Hordeum. Cal. of 2 parallel valve?, aggregate, ternate, with one floret. 

 Central flower only perfect, p. 314. 



Triticum. Cal. of 2 transverse opposite valves, solitan'j many-flowered. 

 p. 315. 



