GRASS FAMILY 



111 



38. Poa lettermani Vasey. 

 Letterman's Bluegrass. Fig. 490. 



Foa lettermani Vasey, Contr. U. S. Xat. Herb. 1: 273. 1893. 



Plants rather soft and lax; culms nume.rous in small 

 dense tufts, smooth, 5-10 cm. tall ; sheaths smooth ; 

 blades mostly flat, 1-3 cm. long, .5-1 mm. wide; 

 panicle purplish, small and narrow, .5-1.5 cm. long, 

 the branches short and appressed ; glumes and lem- 

 mas about 3 mm. long, broad, the lemmas broad aiid 

 toothed at the summit. 



Alpine region of Mount Rainier and Mount Adams; also in 

 Colorado. August. Type locality: Grays Peak, Colorado. 



The viviparous form of Poa biilbosa L. has been found at 

 Bingen and Walla Walla. The spikelets are replaced by dark- 

 purple bulblets. 



66. PANICULARIAHeister: Fabr. PL Hort. Helmst. ed. 2. 373. 1763. 

 [Glyceria R. Br. Prodr. Fl. Nov. Holl. 179. 1810.] 



Spikelets few- to many-flowered, subterete or slightly compressed, the rachilla disartic- 

 ulating above the glumes and between the florets ; glumes unequal, short, obtuse or acute, 

 usually scarious, mostly 1-nerved; lemmas broad, convex on the back, firm, usually obtuse, 

 awnless, scarious at apex, 5-9-nerved, the nerves usually prominent. Usually tall aquatic 

 or marsh grasses, with flat blades and open or contracted panicles. [Latin, referring to 

 the panicled spikelets.] 



Species about 35 in the temperate regions of both hemispheres. Type species, Poa atjuatica L. 



Spikelets linear, usually as much as 1 cm. long; panicles erect. 



Lemmas smooth between the slightly scabrous nerves, thin, 3.5-4 mm. long. 1. 



Lemmas scabrous between the usually distinctly scabrous nerves, firm, 3—6 mm. long. 



Lemmas about 3 mm. long, broadly rounded at summit. 2 



Lemmas 4-6 mm. long, narrowed toward the summit. 3. 

 Spikelets ovate or oblong, usually not over 5 mm. long; panicles nodding. 



Lemmas with 5 prominent nerves. 4. 

 Lemmas with 7 prominent nerves. 



Glumes short and rounded, the lower about 1 mm, long. 



Blades 1-3 mm. wide; culms usually not over 1 meter tall, firm, not succulent. 



5. P. nervata. 



Blades mostly 6-10 mm. wide; cidms mostly 1-3 meters tall, succulent. 6. P. data. 



Glumes oblong, the lower about 2 nun. long, whitish. 7. P. grandis. 



1. Panicularia borealis Nasli. 



p. borealis. 



P. davyi. 

 P. fluitan.i;. 



P. paiiciflora. 



Xonheni Manna-gra.ss. Fig'. 491. 



Panicularia borealis Xash, Bull. Torrey Club 24: 348. 



1897. 

 Glyceria borealis Batchelder, Proc. Manchester Inst. 1: 



74. 1900. 



Culms 30-100 cm. tall, erect from a more or 

 less decumbent and rooting base ; sheaths smooth 

 or slightly scabrous, keeled ; blades flat or usu- 

 ally folded, scabrous above, erect, 3-4 mm. wide ; 

 panicle long and narrow, the branches and 

 slender pedicels appressed ; spikelets narrow, 

 nearly terete, 12-18 mm. long, 1 mm. wide, pale, 

 not purple-tinged; glumes 1-nerved, the first 1.5 

 mm., the second 3 mm. long; lemmas oblong. 4 

 mm. long, 7-nerved, smooth or indi'^tinctly sca- 

 brous on the nerves. 



In shallow water, in the Canadian Zone; New England 

 to central California and northward. June-Aug. Type 

 locality: !Maine. 



