MAXUAL OF THE GRASSES OF THE UNITED STATES 



303 



D. INTERMEDIA. 



D. UNISPICATA. 

 D. CALIFORXICA. 



D. PARRYI. 



Figure 597.— Distribution of 

 Danthonia spicata. 



Lemmas glabrous on tiie back, pilose or the margin only. 



Panicle narrow, the pedicels appressed 4. 



Panicle open, the slender pedicels spreading or reflexed. 



Panicle usually of a single spikelet 7. 



Panicle of 2 to several spikelets 6. 



Lemmas pilose on the back, sometimes sparsely so. 



Glumes mostly 20 to 22 mm long 5. 



Glumes 10 to 17 mm long. 



Sheaths pilose, (rarely glabrous); glumes 12 to 17 mm long. Culms 50 to 



100 cm tall I 3. D. sericea. 



Sheaths glabrous or nearly so; glumes rarely more than 15 mm long. 



Panicle simple or nearly so, usually contracted after anthesis; blades rarely 



more than 15 cm ]ong, commonly less 1. D. spicata. 



Panicle usually compound and somewhat open; blades or some of them 

 more than 15 cm, often as much as 25 cm long 2. D. compressa. 



1. Danthonia spicata (L.) Beauv. Poverty oatgrass. (Fig. 

 596, A.) Culms 20 to 70 cm tall, mostly not more than 50 cm, slender, 



terete; leaves numerous in a basal cluster, the 



blades usually curled or flexuous; sheaths gla- 

 brous or sparsely pilose, with a tuft of long hairs 

 in the throat; blades usually not more than 

 12 cm long, filiform to 2 mm wide, occasionally 

 a few blades 15 to 20 cm long, subin volute or 

 in damp weather flat, glabrous or sparsely 

 pilose; panicle 2 to 5 cm long, rarely longer, 

 the stiff short branches bearing a single spikelet, 

 or the lower longer with 2 (rarely 3 or 4), usually erect after anthesis; 

 glumes 10 to 12 mm long (rarely longer); lemmas 4 to 5 mm long, 

 sparsely villous except the 2-toothed summit, the teeth acuminate to 

 subsetaceous; terminal segment of awn about 5 mm long; palea broad, 

 flat, obtuse, ciliolate, reaching to the base of the awn. % — Dry 

 and sterile or rocky soil, Newfoundland to British Columbia, south to 

 Florida, eastern Texas, and eastern Kansas, in the mountains to 

 New Mexico and Oregon (fig. 597). Variable; tall specimens with 

 longer blades and setaceous teeth resemble D. compressa. A rather 

 stiff western form with subsetaceous teeth has 

 been described as D. thermale Scribn. 



2. Danthonia compressa Austin. (Fig. 596, 

 B.) Culms on the average stouter and taller 

 than in D. spicata, compressed, rather loosely 

 tufted, sometimes decumbent or with short rhi- 

 zomes, 40 to 80 cm tall; sheaths reddish above 

 the nodes, glabrous, or sparsely pubescent on 

 the collar, a conspicuous tuft of white hairs in 

 the throat; blades elongate, some of them commonly 20 to 25 cm long, 

 2 to 3 mm wide, usually flat, sometimes involute and subfiliform, sca- 

 brous; panicle 5 to 8 cm long (rarely to 10 cm), the slender branches 

 bearing 2 or 3 spikelets, contracted after anthesis but looser than in D. 

 spicata; glumes 10 to 14 mm (usually about 12 mm) long; lemma and 

 palea as in D. spicata but the teeth of the lemma aristate, 2 to 3 mm 

 long. % — Meadows, and open woods, Nova Scotia to Quebec, 

 south to the mountains of North Carolina (fig 598). Appears to 

 intergrade with D. spicata. 



3. Danthonia sericea Nutt. Downy oatgrass. (Fig. 599.) 

 Culms erect, densely tufted, 50 to 100 cm tall; sheaths, especially the 

 lower, villous (rarely glabrous); blades 10 to 25 cm long, 2 to 4 mm 



55974°— 35 20 



Figure 598.— Distribution of 

 Danthonia compressa. 



