422 GR AMINES. (GRASS FAMILY.) 



* # Tall perennials (I to 3 feet), with open oblong or pyramidal panicles, the 



rather short and rough branches mostly in Jives, sometimes in twos or threes. 



8. P. pratensis, L. Ste?ns with running rootstocks, and with the sheaths 

 smooth : leaves dark green, the radical very long, those of the stem short, 

 scabrous on the margins; ligule short and blunt : panicle pyramidal; spikelets 

 3 to 5-flo\vered, somewhat crowded and almost sessile : outer glumes acuminate, 

 scabrous on the keel : flowering glume distinctly 5-nerved, silky-hairy on the 

 margins and keel. Across the continent, and one of the most valuable of 

 pasture and meadow grasses. Known variously as "June Grass," "Green 

 Meadow-Grass," "Spear Grass," and "Kentucky Blue-Grass" 



9. P. serotina, P^hrh. Stems tufted, without distinct running root- 

 stocks : leaves narrowly linear, soft and smooth ; ligule elongated, acute : pan- 

 icle 6 to 10 inches long, at length somewhat nodding at apex, often purplish ; 

 spikelets 2 to 4-flowered, all, short-pedicel led : outer glumes narrow: Jlowering 

 glume very obscurely nerved. From the Rocky Mountains eastward across the 

 continent. Quite variable, some Rocky Mountain forms having been described 

 as varieties. Known as " False Red-top " and " Fowl Meadow-Grass." 



10. P. flexuosa, Muhl., var. OCCidentalis, Vasey. Stems erect, rather 

 stout, tufted : sheaths mostly smooth ; leaves broadly linear, 3 to 5 inches 

 long, gradually tapering to a point, rather scabrous : panicle more diffuse, 4 to 

 8 inches long; its branches mostly in twos or threes (sometimes fives), long and 

 capillary, smooth or scabrous, diverging, flower-bearing mostly for the upper 

 third : spikelets 4 to 6-flowered : outer glumes acute, thin, slightly hispid on 

 the keel : Jlowering glume distinctly 3 to 5 nerved, slightly pubescent, rather more 

 so on the keel and margins. Bot. Wheeler Exped. 290. Includes P. flexu- 

 osa (?) of Bot. King Exped. Colorado and Utah. 



* * * Perennials not so tall (1 to 2 feet) : branches of the panicle solitary or 



in pairs. 



11. P. Eatoni, Watson. Allied to the last : stems smooth : sheaths and 

 leaves scabrous; leaves mostly radical and narrowly linear, 3 to 6 inches long, 

 the cauline few and very short : panicle loose and spreading, with short 

 (an inch long or less) branches ; spikelets 4 to G-flowered, purplish : outer glumes 

 acutish : flowering glume very villous on back and margins, obtuse and keeled. 

 Bot. King Exped. 386. In the Wahsatch Mountains, Utah, Nevada, and 

 S. W. Wyoming. 



12. P. arctica, R. Br. Stems erect, slender, very smooth, as are the 

 sheaths and leaves: leaves about two on the stem, narrowly linear, 2 to 3 inches 

 long: panicle 4 to 5 inches long, with longer (lower 2 to 3 inches) capillary 

 branches, which are spreading or reflexed with age : spikelets mostly 3-flowered : 

 outer glumes broadly ovate, rather acute, purple-margined : flowering glume 

 obscurely 3 to 5-nerved, acute, smooth, except pubescent on the keel and lateral 

 nerves. In the mountains of Colorado and far northward. 



42. GRAPHEPHORUM, Desv. 



Perennial and northern or alpine grasses, with linear flat leaves, their 

 sheaths closed at the base, and spikelets in a loose panicle. 



1. G. flexuosum, Thurber. Stem 3 feet high, smooth: leaves 1 feet 

 long, setaceous-acuminate : panicle loosely flowered ; branches scattered ; spike- 



