32 



POACEAE. 



1-3-nerved.; the flowering scales longer than the empty ones, generally with 

 a tuft of cobwebby hairs at the base, 5-nerved, the marginal nerves usually 

 pubescent, often also the dorsal one; palets a little shorter than the scales, 

 2-nerved or 2-keeled. Stamens 3. Styles short, distinct. Stigmas plumose. 

 Grain free, or sometimes adherent to the palet. [Name Greek, for grass or 

 herbage.] A genus of about 150 species, widely distributed in all temperate 

 and cold regions. The English name Meadow-grass is often applied to most of 

 the species. Type species: Poa pratensis L. 



Annual with fibrous roots. 1. P. annua. 



Perennial by running rootstocks. 



Empty scales elliptic-oblong ; flowering scales ovate-lanceolate 



in side-view. 2. P. pratensis. 



Empty scales lanceolate; flowering scales linear in side-view. 3. P. nemoralis. 



1. Poa annua L. Annual Mead- 

 ow-grass. Low^ Spear-grass. (Fig. 

 47.) Culms 2-10' tall, from an an- 

 nual root, erect or decumbent at the 

 base, somewhat flattened, smooth. 

 Sheaths loose, usually overlapping; 

 leaves J'-4' long, wide, smooth; pan- 

 icle i'-4' in length, open, branches 

 spreading, naked at the base; spike- 

 lets 3-5-flowered, li"-2i" long; lower 

 scales smooth, the first narrow, acute, 

 1-nerved, about two thirds as long 

 as the broad and obtuse 3-nerved 

 second one ; flowering scales distinctly 

 5-nerved, the nerves pilose below. 



Common in waste and cultivated 

 places. Naturalized from Europe. Na- 

 tive also of Asia. Widely naturalized 

 in temperate North America. Flowers 

 from spring to autumn. 



2. Poa pratensis L. Kentucky 

 Blue-grass. June-grass. (Fig. 48.) 

 Culms l°-3i° tall, from long running 

 rootstocks; leaves smooth or rough, 

 those of the culm 2'-6' in length, the 

 basal much longer; panicle 2*'-8' long, 

 usually pyramidal, the branches 

 spreading or ascending, sometimes 

 flexuous, divided and spikelet-bearing 

 above the middle; spikelets 3-5-flow- 

 ered, 2"-2i" long, exceeding their 

 pedicels ; scales acute ; flowering scales 

 webbed at the base, 5-nerved, the 

 marginal nerves and mid-nerve silky- 

 pubescent below, the intermediate 

 ones naked. 



ClifEs, south shores near Tucker's 

 Town, abundant in 1909 ; lawn Abbes- 

 ford, 1914. Introduced, probably in 

 hay. Native of the north temperate 

 zone. Flowers in spring and summer. 



