394 



Bulletin Xo. 205 



[March, 



Spikelets 2 to 8 mm. loug, the length never three times the width; panicles 



open and spreading, 

 b. Spikelets 3 to 4 mm. wide; nerves on the lemmas not prominent. 



P. canadensis 



bb. Spikelets 1 to 2.5 mm. wide; nerves on the lemmas very prominent and 



with deep furrows between. 



c. Spikelets 3 to 4 mm. long, the lemmas 1.5 mm. long, glumes short 



and rounded. P. nervata 



cc. Spikelets 4 to 6 mm. long, the lemmas 2 mm. long, glumes oblong. 



P. grandis 

 Sjiikelets 10 to 25 mm. long, the length always more than three times the 



width; panicle narrow, the branches erect. 



b. Spikelets nearly sessile; 15 to 20 mm. long; lemmas firm, hispidulous: 



4 to 4.5 mm. long. P. septentrionalis 



bb. Spikelets slender pediceled; 10 to 15 mm. long; lemmas thin, rough only 



on the nerves. 3.5 to 4 mm. long. P. borealis 



239 



241 



243 



240 



242 



Figs. 230-244. — 239, P. horcalis, inflorescence; 240, P. borealis, 

 241, P. canadensis, spikelet; 242, P. grandis, spikelet; 243, P. nervata, 

 244, P. septentrionalis, spikelet 



/244 



spikelet ; 

 spikelet ; 



Panicularia borealis Nash 

 Slender Manna Grass. (Figs. 239 and 240) 



Culms bent at base and rooting at the nodes, 2 to 5 feet tall: 

 sheaths overlapping, usually smooth, the upper one inclosing the base 

 of the panicle ; blades narrow, 4 to 20 inches long, 2 to 10 mm, broad, 

 usually folded, ending in a sharp point ; panicle very narrow, with the 

 branches erect or appressed ; spikelets 10 to 15 mm. long, the pedicels 

 one-third to two-thirds the length of the spikelets, 7- to 13-fiowered : 

 lemmas thin, 3.5 to 5 mm. long, the nerves rough. 



