1916] Fernald & Weatherby,— Puccinellia 5 



In the following synopsis of the species of Puccinellia of eastern 

 North America only those species which we know from south of 

 Hudson Straits are included, but in the citation of specimens stations 

 in western North America are often indicated, especially in the cases 

 of newly described or newly interpreted species and varieties. The 

 plates which have been most kindly prepared for us by Mr. R. E. 

 Torrey illustrate details of all the species here included and some which 

 have heretofore been ascribed to the region. 



Key to the Species and Varieties of Puccinellia in eastern North 



Ami: rica. 



A. Anther 1.5-2.2 mm. long. 



Flowering culms tall, 2-8 dm. high: branches of the panicle scabrous: 

 lemmas 4-5 mm. long, pubescent on the nerves below 



1. P. maritima. 

 Flowering culms low, 0.4-1 dm. high: branches of the panicle smooth: 



lemmas 2.8-3 mm. long, glabrous 2. P. phryganodes. 



A. Anther 0.5-1 mm. long (1-1.2 mm. in P. lucida). B. 

 B. Grain 1.4-1.7 mm. long. C. 



C. Lower branches of the comparatively short panicle (0.2-1.6 dm. 

 long) densely flowered nearly to the base or at least below the middle: 

 lemmas thick and coriaceous, without a broad hyaline tip; the mid- 

 nerve reaching the apex, often excurrent as a very short mucro. 



3. P. fasciculata. 

 C. Lower branches of the panicle floriferous chiefly above the middle, 

 or, if much below, loosely flowered and the panicle much elongated 

 (2-3 dm. long) : lemmas thin and membranaceous in texture (firm in 

 P. laurentiana and sometimes in P. paupercula) , or at least with a 

 broad hyaline tip; the midnerve not excurrent. D. 

 D. Lemmas erose-ciliolate or serrulate under a lens. E. 



E. Glumes and lemmas truncate, erose-ciliolate under a lens. 



Mature panicle broadly ovoid, loose, its branches spreading 

 or reflexed. 

 Leaves of the culm 2-6 mm. wide, flat: panicle 0.8-2 dm. 



long: lemmas 2-2.5 mm. long 5. P. distans. 



Leaves of the culm 2 mm. wide or less, becoming more or 

 less involute: panicle 4-9 cm. long: lemmas 1.5-2 mm. 



l° n g (5.) P. distans, var. tenuis. 



Mature panicle slender-cylindric to ellipsoid, dense, its 



branches erect or ascending 6. P. coarctata. 



E. Glumes and lemmas tapering to an acute or obtusish tip, not 

 truncate, erose-serrulate: panicle-branches erect or ascend- 

 ing, rarely spreading. 



