164 



GRAMINEAE (GRASS FAMILY) 



179. B. tectorum 

 Spikelet x 1. 



§ 2. STENOBROMUS 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 ; calms usually taller and geniculate at base ; panicle 

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

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

 lemma scabrous or scabrous-puberulent ; au) n 2-S cm. long. — 

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

 also on Pacific coast. June. (Nat. from. Eu.) 



10. B. RUBENS L. Panicle erect, compact, ovoid, visually 

 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, vjith v^eak 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 o-*.^-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, 

 at least the lower, usually sparsely retrorse-pilose ; blades 1.5-3 dm. 

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

 panicle large, lax, nodding ; spikelets mostly l-\l-flowered, 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, /?f)';ii.s-/i^d at the summit with a pubescent ring, otherwise sparsely 

 pubescent, and in having broader and distinctly 1-nerved lemmas, the pubes- 

 cence more silky and increasing in density tovmrd 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., anrl Tex. 



15. B. Kalmii Gray. (Wild Chess.) Culm slender, 0.5-1 m. 

 high ; sheaths and blades conspicuously or sparingly villous ; pani- 

 cle 7-10 cm. \o\vi, ; spikelets ^voo\)m^ on capillary peduncles, closely 

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



distinctly '^-nerved, the second ^)-nerved ; lemma 8-10 nmi. long, 7-nerved, obtuse ; 

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

 north w. June, July. Fig. 181. 



16. B. ERECTus Iluds. Culms erect. 6-9 dm. higli, glabrous; sheaths nearly 

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

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



180. B. ciliatus 



x%. 



Spikelet and 



lemma. 



181. B. Kalmii. 

 Spikelet x 1. 



