842 GRAMlKBiE. (GRASS FAMILY.) 



* ♦ * * Spikelets in spikes or heads, ojtcn with an involucre of sterile glumes or &pikelets. 

 56. ECHINARIA. Heads globular to ovate, .01 to .015 long, echinate with pungent 



awns of pales. 

 .')7. AMMOCHLOA. Heads globular to oblong, .005 to ,01 long; spikelets 2-ranked ; 



glumes with a keel to one side. 



58. HESLERIA. If Alpine plants with spikelets in a cylindrical. spike, .03 long. 



59. LAMARCKIA. Fertile spikelets 2-flowered, sterile oblong, .01 long, composed of 



obovate, obtuse, 2-ranked pales ; branches of panicle and spikelets nodding, loose. 



60. CYNOSURUS. Fertile spikelets 2-5-flowered, sterile ovate to oblong, composed of 



2-ranked, or somewhat spirally arranged, long-awned pales. Spikelets in ovate to 

 oblong heads. 

 •♦♦*♦* Spikelets variously panicled or spiked, or in heads, destitute of an involucre. Lower pale 

 muticous, or awned at or beneath tip. 



61. KGilLERlA. Spikelets in cylindrical, branched, often lobed spikes. 



62. MOLINIA. 2f Panicles long, very narrow, interrupted. 



63 SPHiENOPUS. Panicles diffuse, with capillary, 2-3-forked branches. Pedicels club- 

 shaped, crowned with persistent glumes. 



64. CATABROSA. 2f Aquatics, with diffuse panicles of 2-3- (rarely 1-) flowered spikelets ; 



lower pales truncate-denticulate. 



65. EKAGROSTIS. If Panicles diffuse or spiked j spikelets 3- oo-flowered, imbricated ; 



axis and upper pales persistent ; lower pales falling with caryopsis. * 



66. MELICA. 21 Panicles spike-like; spikelets 2-5-flowered; the lower 1-2 fertile, the 



upper 1-3 consolidated into an oblong or turbinate mass. 



67. ^LUROPUS. 2f Low plants, with rigid, 2 ranked leaves, and globular, ovate, 



oblong, or cylindrical spikes. 



68. DACTYLIS. 2f Spikelets in ovate to oblong, dense, compound spikes or heads, 



69. SCLEROCHLOA. Spikelets in a one-sided, spike-like panicle. 



70. BRIZA. 2f Spikelets ovate-oblong, composed of concave, muticous, imbricated 



flowerets, and arranged in loose panicles with capillary branches. 



71. gCIIISMUS. Spikelets in a short, dense, spike-like panicle. Lower pales 2-tootIicd 



or -lobed, with or without awn. 



72. PO.\. 2|! Spikelets ovate to ovate-oblong, with more or less imbricated flowerets, 



in more or less open panicles. Pales muticous. 



73. GLYCERIA. 2j| Aquatics, with oblong-linear spikelets; flowerets imbricated. 



Panicles open. Glumes and pales muticous. * 



74. ATROPIS. 2f Herbs with oblong spikelets, flowerets 4-6, imbricated. Panicles open. 



Glumes and pales muticous. 



75. FE8TUCA. 2( Herbs with oblong spikelets, glumes muticous, lower pales muticous 



or short-awned. 



76. VULPIA. Distinguished from Festuca by long-awned pales and sometimes upper 



glume awned. 



77. NARDURUS. ;^Spikelets alternate (the stalks immersed in excavations of the rachis) ; 



flowerets divergent. Lower pale muticous or short-aristate. 



78. CATAPODIUM. Spikelets nearly sessile in excavations of rachis; flowerets imbri- 



cated. Lower pale muticous. 



79. bCLEROPOA. Panicles loose, one-sided or forked. Spikelets muticous, mucronulate 



or aristulate, 



80. BROMUS. If @ Panicles various. Spikelets oo -flowered, large, awned. 



81. BRACHYPODIUM. 2f Panicle reduced to a raceme of 2-ranked, more or less 



approximated, oo -flowered spikelets. 



