MANUAL OF THE GRASSES OF THE UNITED STATES 



347 



pie, about 2.5 mm. long; lemma 1.5 

 mm. long, awnless; palea minute. % 

 — Rocky creeks and mountain slopes 

 at high altitudes; British Columbia 

 and Alberta to Colorado and Cali- 

 fornia. Included in A. rossae Vasey in 

 Manual, ed. 1. 



Figure 482. — Agrostis varia- 

 bilis. Panicle, X 1; glumes 

 and floret, X 5. (Hitchcock 

 23178, Wyo.) 



Figure 483. — Agrostis exarata. Panicle, X 1; glumes 

 and floret, X 5. (Davy 4357, Calif.) 



24. Agrostis exarata Trin. Spike 

 bent. (Fig. 483.) Culms 20 to 120 

 cm. tall, slender to relatively stout, 

 mostly tufted; sheaths smooth to 

 somewhat scabrous; ligule to 6 mm. 



long; blades flat, 2 to 10 mm. wide, 

 usually scabrous; panicle narrow, 

 from somewhat open to dense and in- 

 terrupted, 5 to 30 cm. long; glumes 

 subequal, 2.5 to 4 mm. long, acu- 

 minate to awn-tipped, scabrous on 

 the keel, nearly smooth to scabrous 

 on the back; lemma 1.7 to 2 mm. long, 

 the midnerve ending above the middle 

 or excurrent as a prickle or short awn, 

 sometimes the nearly straight awn ex- 

 ceeding the glumes; palea minute. 

 % ■ — Moist open ground, at low and 

 medium altitudes, South Dakota and 

 Nebraska to Alberta and Alaska, 

 south to Texas, California, and Mex- 

 ico. Common and extremely variable, 

 ranging from slender plants with nar- 

 row blades and few-flowered panicles 

 (A. scouleri Trin.) to robust plants a 

 meter or more tall, with dense pan- 

 icles as much as 30 cm. long (A. 

 grandis Trin.). The specimens in the 

 Trinius Herbarium from Unalaska 

 (type) and Sitka, with culms 25 to 60 

 cm. tall and narrow but not dense 

 panicles, the lemmas awnless, repre- 

 sent about the center of the range of 

 variation. Awnless and awned spike- 

 lets are found in the same panicle. 



Agrostis exarata var. pacifica 

 Vasey. Lemma with a straight or 

 weakly geniculate awn exceeding the 

 glumes; habit of the plant, height, and 

 foliage as in the species, the variations 

 similar. % — Frequent from Van- 

 couver Island and Washington to 

 California, rare elsewhere: Canada, 

 the Aleutians, Nebraska, Idaho, Ari- 

 zona. 



Agrostis exarata var. monolepis 

 (Torr.) Hitchc. Panicle narrow, dense, 

 often interrupted; glumes mostly 

 awn-tipped; awn of lemma exceeding 

 the glumes 1.5 to 2 mm. % — 

 Washington to California. 



25. Agrostis ampla Hitchc. (Fig. 

 484.) Resembling A. exarata var. 

 pacifica, the panicle looser, the 

 branches verticillate, some of them 5 

 to 9 cm. long, the spikelets less 

 crowded at the base; glumes 3.5 to 

 4.5 mm. (the first exceeding the sec- 

 ond), acuminate to awn-tipped; lem- 



