Genus 96. 



GRASS FAMILY. 



263 



Spikelets ovate or oblong, 4" long or less. 



Flowering scales very broad, obscurely or at lea'st not sharply nerved. 

 Panicle open, the branches ascending or spreading, often drooping. 



Spikelets 3-5-flowered ; lowest flowering scale about 1" long. 1. P. laxa. 



Spikelets 5-12-flowered ; lowest flowering scale about lyi" long. 2. P. canadensis. 

 Panicle contracted, the branches erect. 3. P. obtusa. 



Flowering scales narrow, sharply and distinctly 7-nerved. 



Panicle elongated, its branches erect or appressed. 4. P. Torreyana. 



Panicle not elongated, open, its branches spreading or drooping, rarely erect. 

 Scales about 1" long, obtuse or rounded at the apex. 



Spikelets i}4" long or less ; branches of the panicle often drooping. 



5. P. nervata. 

 Spikelets 2"— 3" long ; branches of the panicle ascending or spreading. 



6. P. grandis. 

 Scales i^"-i^" long, truncate and denticulate at the apex. 7. P. pallida. 



Spikelets linear, 6" long or more. 



Flowering scales i}4"-2j4" long, obtuse, equalling or exceeding the obtuse palet. 



Flowering scales firm, hispidulous all over, truncate at the apex. 8. P. septentrionalis. 



Flowering scales thin, hispidulous on the nerves only, obtuse at the apex. 



9. P. borealis. 

 Flowering scales s"-4" long, usually shorter than the acuminate palet. 



Flowering scales obtuse,, about 3" long, a little exceeded by the palet. 10. P. fluitans. 

 Flowering scales acute, about 4" long, much exceeded by the palet. 11. P. acutiflora. 



i. Panicularia laxa Scribn. Northern Manna-grass. Fig. 632. 



Panicularia laxa Scribn. Bull. Torr. Club 21 : 37. 1894. 



Glyceria laxa Scribn. 

 1894. 



Redf. & Rand, Fl. Mt. Desert, 180. 



Culms 2°-4° tall, erect, simple, smooth or slightly 

 scabrous. Sheaths overlapping, rough; ligule i"-i" 

 long; blades 8'-i5' long, 2"-4" wide, very rough; 

 panicle j'-g' in length, the branches spreading or as- 

 cending, the lower 3'-6' long; spikelets 3-5-flowered, 

 about 2" long; empty scales unequal, scarious, acute, 

 i-nerved, the first one-half to two-thirds the length of 

 the second ; flowering scales broad, about 1" long, 

 twice the length of the second scale, obtuse, ob- 

 scurely 7-nerved. 



In water or wet soil, Nova Scotia to Maine, New Jersey 

 and Pennsylvania. Aug. 



2. Panicularia canadensis (Michx.) Kuntze. Rattlesnake-grass. Fig. 633. 



Briza canadensis Michx. Fl. Bor. Am. 1 : 71. 1803. 

 Glyceria canadensis Trin. Mem. Acad. St. Petersb. (VI.) 



1 : 366. 1831. 

 Panicularia canadensis Kuntze, Rev. Gen. PI. 783. 1891. 



Culms 2°-3° tall, erect, simple, smooth or slightly 

 scabrous. Sheaths shorter than the internodes, those 

 at the base of the culm overlapping; ligule 1" long, 

 truncate ; blades 6'-i° long or more, 2"-^" wide, 

 rough; panicle si'-io' in length, the branches spread- 

 ing, ascending or often drooping, 2j'-s' long; spikelets 

 5-12-flowered, 2i"-4" long, flattened, turgid; empty 

 scales unequal, acute, i-nerved; flowering scales, broad, 

 W-2" long, obtuse or acutish, obscurely 7-nerved. 



In swamps and marshes, Newfoundland to Minnesota, 

 south to New Jersey and Kansas. The handsomest species 

 of the genus. Ascends to 5000 ft. in the Adirondacks. 

 Tall Quaking-grass. July-Aug. 



