90 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



Plants annual. 

 Lemmas narrow, gradually acuminate. 



Second glume usually less than 1 cm. long; pedicels capillary, fiexuous. 



4. B. tectorum. 

 Second glume more than 1 cm. long; pedicels not capillary and flexuous. 



Awn about 2 cm. long; first glume about 8 mm. long 5. B. sterilis. 



Awn 3-5 cm. long; first glume about 15 mm. long 9. B. villosus. 



Lemmas broad, abruptly narrowed above, glabrous. 



Sheaths glabrous 6. B. secalinus. 



Sheaths pilose. 



Panicle rather dense 8. B. racemosus. 



Panicle open. 



Lemma smooth, the awn straight 7. B . commutatus. 



Lemma scabrous, the awn divergent 10. B. japouicus. 



1. Bromus unioloides (Willd.) H. B. K. Rescue grass. 

 Occasionally escaped from cultivation in the vicinity of Arlington Farm. Culti- 

 vated in the southern states as a forage grass. Originally from S. Amer. 



2. Bromus inermis Leyss. Awnless brome grass. 

 Occasionally escaped from the experimental plots or propagating grounds. Culti- 

 vated in the northwestern states as a forage grass. Originally from Eur. 



3. Bromus purgans L. 



Rich or rocky woods; frequent. June-July. Eastern U. S. {B. ciliatus purgans 

 A. Gray; B. ciliatus of Ward's Flora.) 

 3a. Bromus purgans incanus Shear. 



Rocky woods along the Potomac; infrequent. Aug. Pa. to Va. and westward. 



4. Bromus tectorum L. 



A weed in waste ground; infrequent. June. Introduced from Eur. 



5. Bromus sterilis L. 



Waste places; rare; Old Observatory (SfeeZe) ; Holmead (Ward); Union town ( TTarc/) . 

 June. Introduced from Eur. 



6. Bromus secalinus L. Chess. 

 Fields and waste ground; frequent. June. Introduced from Eur. 



Also called cheat. 



7. Bromus commutatus Schrad. 



Waste places; frequent. June. Introduced from Eur. 



8. Bromus racemosus L. 



Waste places; infrequent. June. Introduced from Eur. {B. mollis of Ward's 

 Flora.) 



9. Bromus villosus Forsk. 



Waste places; becoming frequent from College Park to Beltsville. June. Intro- 

 duced from Eur. 



10. Bromus japonicus Thunb. 



Waste places; near Suitland. July. Introduced from Eur. 



60. LOLIITM L. Rye grass. 



1. Lolium perenne L. Perennial rye grass. 



Grassland and open ground; common. June. Cultivated as a lawn grass, especially 

 in parks; originally from Eur. 



61. AGROPYRON Beauv. Wheat grass. 



1. Agropyron repens (L.) Beauv. Couch grass. 



Open ground and gras.sland; frequent. June. Introduced from Eur. (Triticum 

 repens L.) 



A troublesome weed on account of its creeping rootstocks. Also called quack, 

 quitch, and quick grass. 



