104 



MISC. PUBLICATION 200, U. S. DEPT. OF AGRICULTURE 



1. Annuae. — Annuals; culms seldom 



more than 50 cm. tall; panicles 



open (contracted in P. bigelovii). 



1. Poa bolanderi Vasey. (Fig. 115.) 



Culms erect, 15 to 60 cm. tall; 



sheaths glabrous; blades relatively 



Figure 115. — Poa bolanderi. Panicle, X 1; floret, 

 X 10. (Swallen 799, Calif.) 



short, 3 to 5 mm. wide, abruptly 

 narrowed at tip; panicle about half 

 the length of the entire plant, at 

 first contracted, finally open, the 

 branches few, distant, glabrous, stiff- 

 ly spreading, naked below; spikelets 

 usually 2- or 3-flowered, the inter- 

 nodes of the rachilla long; glumes 

 broad, 2. and 3 mm. long; lemma 

 scantily webbed at base, acute, the 

 marginal nerves rather indistinct, the 

 intermediate nerves obsolete. O 

 — Open ground or open woods, 1,500 

 to 3,000 m., Washington and Idaho 

 to western Nevada and the southern 

 Sierras in California. 



2. Poa howellii Vasey and Scribn. 

 Howell bluegrass. (Fig. 116.) 

 Culms 30 to 85 cm. tall; sheaths 

 retrorsely scabrous to glabrous; blades 

 wider than in P. bolanderi, gradually 

 acuminate; panicle one-third to half 

 the entire height of the plant, open, 

 the branches in rather distant fas- 

 cicles, spreading, scabrous, naked 

 below, some short branches inter- 

 mixed; spikelets 3 to 5 mm. long, 

 usually 3- or 4-flowered; glumes nar- 

 row, acuminate, 1.5 and 2 mm. long; 

 lemmas webbed at base, 2 to 3 mm. 

 long, ovate-lanceolate, pubescent on 

 the lower part, the nerves all rather 

 distinct. — Rocky banks and 

 shaded slopes, mostly less than 1,000 

 m., Vancouver Island to southern 

 California, especially in the Coast 

 Ranges. 



3. Poa bigelovii Vasey and Scribn. 



BlGELOW BLUEGRASS. (Fig. 117.) 



Culms erect, 15 to 35 cm. tall; blades 

 1 to 5 mm. wide; panicle narrow, 

 interrupted, 7 to 15 cm. long, the 

 branches short, appressed; spikelets 

 about 6 mm. long; glumes acuminate, 

 4 mm. long, 3-nerved; lemmas about 

 3 mm. long, sometimes 4 mm., webbed 

 at base, conspicuously 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 

 Colorado, Nevada, and southern Cali- 

 fornia; northern Mexico. 



