FLORA OF THE DISTRICT OF COLUMBIA. 89 



4. Panicularia canadensis (Michx.) Kuutze. Rattlesnake grass. 

 Swales below the fall line; infrequent. Summer. Northern states, south to ^Id. 



{Glyceria canadensis Trin.) 



5. Panicularia nervata (Willd.) Kuutze. 



Swales and wet places; frequent. May-June. Throughout the U. S. {Glyceria 

 nervata Trin.) 



6. Panicularia pallida (Torr.) Kuntze. 



Swales and stream borders; rare; Bladensburg {Steele). June. Northern states, 

 south to Va. {Glyceria pallida Trin.) 



48. FESTTJCA L. Fescue grass. 



Plants annual. 

 Glumes somewhat unequal, the lower 3 mm. long; spikelets 5-13-flowered ; lemma 

 without scarious margin; awn usually not longer than the lemma. 



1. F. octoflora. 

 Glumes very unequal, the lower 1.5-2 mm. long; spikelets 1-5-flowered ; lemma 



scarious-margined; awn about twice as long as the lemma 2. F. m5ruros. 



Plants perennial. 

 Blades involute; panicle short and contracted. 



Culms erect, pale at base 3. F. ovina. 



. Culms decumbent and usually purplish at base 4. F. rubra. 



Blades fiat; panicle long and narrow, or open with spreading branches. 



Lemmas 5-7 mm. long; panicle narrow, with short erect branches. .6. F. elatior. 



Lemmas about 4 mm. long; panicle very loose, with long spreading or drooping 



branches 6. F. obtusa. 



1. Festuca octoflora Walt. 



Open or sterile ground; common. May-June. Throughout the U. S. {F. tenella 

 Willd.) 



2. Festuca myuros L. 



Open ground; frequent. June. Eastern states; naturalized from Eur. 



3. Festuca ovina L. Sheep fescue. 

 Pastures and grassland; infrequent. June. Introduced from Eur.; occasionally 



cultivated as a pasture grass. 



4. Festuca rubra L. Red fescue. 

 Sometimes cultivated in grass mixtures; occasionally escaped. June. Native of 



Eur. 



5. Festuca elatior L. Meadow fescue. 

 Grassland and open ground; frequent. June. Cultivated as a meadow grass; 



introduced from Eur.; well established in many places. 



6. Festuca obtusa Spreng. 



Rocky or rich woods; frequent above the fall line. May-June. Eastern states. 

 {F. nutans Willd.) 



49. BROMUS L. Brome grass. 



Spikelets much flattened, the lemmas keeled, the awn not more than 2 mm. long. 



1. B. unioloides. 

 Spikelets terete or slightly flattened, the lemmas not keeled or keeled only toward 

 the apex, the awn conspicuous (except in B. inermis). 

 Plants perennial. 

 Creeping rootstocks present; lemma glabrous, awnless or mucronate. 



2. B. inermis. 

 Creeping rootstocks wanting; lemma pubescent, awned. 



Sheaths usually not overlapping, rather loosely pilose 3. B. purgans. 



Sheaths overlapping, densely soft-pilose 3a. B. purgans incanus. 



