HOW TO KNOW THE GRASSES 



38b. Main panicle branches branching again below the middle. Fig. 223. 



Agrostis perennans (Walt.) Tuck. 



Perennial; tufted; culms 20 — 80 cm. tall; 

 panicles usually delicate and lace-like, 

 especially in shade-grown plants. Lem- 

 mas rarely awned. Dry open fields and 

 woodlands. July — October. 



Agrostis oregonensis Vasey is similar, 



but larger and more vigorous. Marshes; 



Montana to British Columbia, southward 

 to Wyoming and California. 



Figure 223 



39a. Glumes minute, less than 1/5 as long as the lemma 



40 



to - 



39b. Glumes hall as long as the lemma or longer 41 



40a. Rachilla extending beyond the palea of the floret as a bristle; 

 erect, broad-leaved forest grass. Fig. 224. 



BTacbyelytTum eiectum fSchreb.) Beauv. 



Perennial; tufted; culms 60 — 100 cm. tall; leaf 

 blades 10 — 15 mm. wide, flat, rather light green; 

 leaf sheaths and blades usually hairy; panicles 

 slender, 5 — 15 cm. long, with erect branches; 

 first glume nearly absent; second glume up to 

 2 mm. long; floret cylindrical, firm, about 1 cm. 

 long, with an awn 1 — 2 cm. long. Typical B. 

 erectum is found mostly south of the glaciated 

 areas of the eastern United States. The lemmas 

 have stout, stiff hairs along the nerves and are 

 otherwise glabrous. It grows in scattered stands 

 in upland woods. June — July. 



Var. septentrionale Babel grows mostly north 

 of the glacial boundary, or southward in the 

 mountains. The lemmas are sparsely and uni- 

 formly covered with minute appressed hairs or 

 are nearly glabrous. Moist thickets and swampy 

 woods. Also known from Japan. 



Figure 224 



119 



