MANUAL OF THE GRASSES OF THE UNITED STATES 



105 



Figure 164.— Distribution of 

 Poa bigelovii. 



ously pubescent on the lower part of keel and lateral nerves, sometimes 

 sparsely pubescent on lower part of internerves. O — Open 

 ground, at medium altitudes, Oklahoma and western Texas to Colo- 

 rado, Nevada, and southern California; northern Mexico (fig. 164). 

 4. Poa chapmaniana Scribn. (Fig. 165.) Plant drying pale or 

 tawny; culms densely tufted, slender, 10 to 30 cm tall; blades 1 to 

 1.5 mm wide; panicle oblong-pyramidal, 3 to 8 cm long, open, the 



lower branches spreading ; 



spikelets 3 to 4 mm long, 



mostly 3- to 5 -flowered; 



glumes 2 and 2.5 mm long; 



lemmas about 2 mm long, 



webbed at base, strongly pu- 

 bescent on the keel and lat- 

 eral nerves, the intermediate 



nerves obscure ; anthers 0.1 to 



0.2 mm long, o — Open 



ground and cultivated fields, 



Delaware to Iowa, south to 



Georgia and Texas (fig. 166). 

 5. Poa annua L. Annual 



bluegrass. (Fig. 167.) Tuft- 

 ed, bright green, erect to 



spreading, sometimes rooting 



at the lower nodes, usually 



5 to 20 cm tall, sometimes 



taller, forming mats; culms 



flattened; blades soft, lax, 



mostly 1 to 3 mm wide ; pan- 

 icle pyramidal, open, 3 to 7 



cm long; spikelets crowded, 



3- to 6-flowered, about 4 mm 



long; first glume 1.5 to 2, the 



second 2 to 2.5 mm long; 



lemma not webbed at base, 



distinctly 5-nerved, more or 



less pubescent on the lower 



half of all the nerves, the 



long hairs on the lower part 



of the keel sometimes simulat- 

 ing a web; anthers 0.5 to 1 



mm long, o — Open ground, 



lawns, pastures, waste places, 



and openings in woods, New- 

 foundland and Labrador to 



Alaska, south to Florida and 

 California ; tropical America at high altitudes; introduced from Europe. 

 In warmer parts of the United States the species thrives in the winter; 

 in intermediate latitudes it is a troublesome weed in lawns, growing 

 luxuriantly in spring, drying in early summer and leaving unsightly 

 patches. 



Figure 165.— Poa chapman- 

 iana. Panicle, X 1; floret, 

 X 10. (V. H. Chase 3557, 



m.) 



Figure 163.— Poa 62^- 

 lorii. Panicle, X 1; 

 floret, X 10. (Fendler 

 931, X.Mex.) 



Figure 166.— Distribution of 

 Poa chapmaniana. 



