164 GRAMINEAE (GRASS FAMILY) 



2. STENOBR6MUS Griseb. Annuals or biennials, with narrow glumes 

 and lemmas and long awns. Introduced. 



8. B. TECT6RUM L. Culms slender, tufted, 3-6 dm. high ; sheaths and blades 

 pubescent ; panicle broad, rather dense, secund, drooping, 6-15 cm. long ; spike- 

 lets 13-20 mm. long, nodding ; lemma pubescent ; awn 13-15 mm. 

 long. Waste places, Me. to 111., and south w. (Nat. from Eu. ) 

 FIG. 179. 



9. B. STERILIS L. Similar to the preceding, sometimes less 

 pubescent; culms usually taller and geniculate at base ; panicle 

 1-2 dm. long, broad, lax, drooping, the slender branches usually 

 bearing but one spikelet; spikelets 2.5-3.5 cm. long, drooping; 

 lemma scabrous or scabrous-puberulent ; awn 2-3 cm. long. 

 Waste places and river banks, Mass, to D. C., O., and 111.; 

 1T9. B. tectorum. also on Pacific coast. June. (Nat. from. Eu.) 

 Spikelet x l. 10. B. RUBENS L. Panicle erect, compact, ovoid, usually 



purplish, 4-7 'cm. long ; awns about 2 cm. long. Waste ground, 

 N. Billerica, Mass. (Swan) ; introduced on Pacific coast. (Adv. from Eu.) 



3. ZERNA (Panzer) Ledeb. Short-lived erect perennials, with weak drooping 

 panicles and more or less pubescent florets. Nearly all native. 



11. B. ciliatus L. Culms rather slender, 7-12 dm. high ; sheaths retrorsely 

 pubescent or nearly smooth ; blades 2.5-3.5 dm. long, 1 cm. wide, typically 

 sparse pilose on both surfaces, but sometimes almost smooth ; panicle broad, 

 lax and drooping, about 1.5-2.5 dm. long, branches spikelet-bearing 



near the ends; spikelets 5-Q-flowered, 1.5-2.2 cm. long; glumes 

 narrow, smooth; lemmas 10-12 mm. long, smooth on the back, 

 ciliate-pubescent along the margins, distinctly 3-nerved or faintly 

 5-7-nerved, obtuse and slightly bifid at the apex ; awn straight, 

 3-5 mm. long. Moist woods and banks, Nfd. to N. Y., w. to 

 Man. and Minn. July, Aug. FIG. 180. 



12. B. purgans L. Culms rather stout, 7-14 dm. high ; sheaths, m B - s cllia 

 at least the lower, usually sparsely retro rse-pilose ; blades 1.5-3 dm. . x '*' 

 long, 5-15 mm. wide, pubescent on the nerves above or smooth ; 8 P lkelet ai 

 panicle large, lax, nodding ; spikelets mostly 7-ll-floicered, 2-2.5 



cm. long ; glumes sparsely pubescent; lemmas 10-12 mm. long, acute or sub- 

 acute, densely pubescent all over, distinctly 5-nerved, or another pair of nerves 

 showing at maturity, emarginate ; awn straight, 4-6 mm. long. (B. ciliatus, var. 

 Gray.) Moist rocky woodlands, w. N. E. to Fla., w. to Wyo. and Tex. 



13. B. altissimus Pursh. Differs from the preceding in having overlapping 

 sheaths, furnished at the summit with a pubescent ring, otherwise sparsely 

 pubescent, and in having broader and distinctly 7-nerved lemmas, the pubes- 

 cence more silky and increasing in density toward the base. (B. 

 purgans, var. latiglumis Shear.) Wooded hills, Ct. to Pa., w. to 

 Mont, and Mo. 



14. B. incanus (Shear) Hitchc. Similar to the preceding, 

 sheaths densely and softly short-pilose; spikelets much as in B. 

 purgans, but flowering later than that species, with which it is as- 

 sociated. (B. purgans, var. Shear.) Wooded hills, Pa. to Va., 

 S. Dak., and Tex. 



15. B. Kalmii Gray. (WILD CHESS.) Culm slender, 0.5-1 m. 

 181 B "Kalmii h ig n ' sneatns and blades conspicuously or sparingly villous ; pani- 



'., ' 1 ' cle 7-10 cm. long ; spikelets drooping on capillary peduncles, closely 



7-12-flowered, 1.5-2.5 cm. long, densely silky all over; first glume 



distinctly 3-nerved, the second 5-nerved ; lemma 8-10 mm. long, 7-nerved, obtuse ; 



awn straight, 2-3 mm. long. Dry ground, w. N. E. to Pa., Mo., Minn., and 



northw. June, July. FIG. 181. 



16. B. ERECT us Huds. Culms erect, 6-9 dm. high, glabrous ; sheaths nearly 

 glabrous; blades narrowly linear, sparingly pilose; panicle 1-2 dm. long, with 

 few ascending branches ; spikelets narrow ; first glume l-nerved, second 3-nerved ; 



