164 



THE TRUE GRASSES. 



grasses. 



FIG. 86. Poapratensis L. 

 Fruiting bract in cross-sec- 

 tion. (After Nees, Gen. 

 Germ., I. 56.) 



P. pratensis L., " June grass," " Kentucky Blue 

 grass" (Fig. 86), has underground 

 runners, smooth sheaths, and a 

 short ligule. P. trivialis L. has 

 aerial runners, rough sheaths, and 

 a long ligule. P. alpina L. has no 

 runners, its leaves are obtuse and 

 spikelets large ; found in the high 

 mountains of the northern hemi- 

 sphere and in the Arctic region. 

 The largest species of the genus is 

 P. ftabdlata Hook. (Dactylis c&spi- 

 tosa For st.) the "Tussock grass" 

 of the Falkland, Fire Islands, and 

 Kerguelen Laud. This grass forms 

 great tufts which reach 2 m. in 

 height, and its leaves are arranged 



like a fan. Its culture is remunerative only where the 



summers are very moist. 



Sec. III. Dioicopoa. Dioecious, but without any other 



difference between the two sexes. Natives in America. 



P. Chilensis Trin., P. lanuginosa Poir. (Poidium Nees is a 



scantily -flowered Poo). 



259. (257) Colopodium Trin. (Arctophila Kupr.). Spike- 

 lets 1-2-flowered, loosely panicled; rather small and 

 bright-colored. Flowering glumes broad, very obtuse, 

 membranaceous, awnless ; ovary naked. Habit of Poa. 



Species twelve, in the Orient and central Asia, espe- 

 cially on high mountains ; two species (C.fulvum and C. 

 pendidinum Gris.) are arctic, forming a peculiar section 

 (Arctophila} with the callus of the flowering glume hairy. 



260. (258 ) Dupontia Brown. Differs from the preced- 

 ing genus only in the longer empty glumes. Callus of the 

 flowering glumes distinctly hairy ; panicles contracted. 



Species two, D. Fischeri Brown and D. psilosantha 

 Kupr., in the arctic zone. 



261. (258 ) Scolochloa Link. Spikelets 3-4-flowered, 

 lanceolate ; panicles loose ; flowering glumes rigid, not 

 keeled, callus hairy ; ovary hairy. Tall, reed-like grasses. 



Species two, in the northern temperate zones of the 





