GRAMINEJE. (GRASS FAMILY.) 619 



w- *+ Upper glume shorter than the lower : perennials, simple-stemmed, 2 - 4 high. 



6. A. purpurascens, Poir. Glabrous; leaves rather involute; flowers 

 in a (10'- 18') long spiked panicle; awns much longer than the flower, the middle 

 one about 1' long. (A. racemosa, Muhl. A. Geyeriana, Steud.) Massachu- 

 setts to Michigan, Illinois, and southward : common. 



7. A. lanata, Poir. Tall and stout ; leaves tardily involute, rough on the 

 upper side, rigid; sheaths woolly ; panicle (l-2 long) spike-like or more com- 

 pound and open; middle awn (I' long) longer than the flower. Salisbury, 

 Maryland, W. M. Canby, and southward. 



* * Awns united below into one, jointed with the apex ofthepalet: root annual. 



8. A. tuberculdsa, Nutt. Culm branched below (6'- 18' high), tumid 

 at the joints ; panicles rigid, loose ; the branches in pairs, one of them short and 

 about 2-flowered, the other elongated and several-flowered; glumes (1'long, in- 

 cluding their slender-awned tips longer than the palet; which is tipped with 

 the common stalk (about its own length) of the 3 equal divergently-bent awns 

 (l'-2' long) twisting together at the base. Sandy soil, E. Massachusetts to 

 New Jersey ; also Wisconsin, Illinois, and southward. 



17. S PAH TIN A, Schreber. CORD or MARSH GRASS. (PL 9.) 



Spikelets 1 -flowered, without a rudiment, very much flattened laterally, spiked 

 in 2 ranks on the outer side of a triangular rhachis. Glumes strongly compressed- 

 keeled, acute, or bristle-pointed, mostly rough-bristly on the keel ; the upper one 

 much larger and exceeding the pointless and awnless palets, of which the upper 

 is longest. Squamulae none. Stamens 3. Styles long, more or less united. 

 Perennials, with simple and rigid reed-like culms, from extensively creeping 

 scaly rootstocks, racemed spikes, very smooth sheaths, and long and tough 

 leaves (whence the name, from (nraprivr], a cord, such as was made from the 

 bark of the Spartium or Broom.) 



* Spikelets compactly imbricated, very rough-hispid on the keels: spikes (2' -4' long) 

 more or less peduncled: culm and elongated leaves rigid. 



1. S. cynosuroides, Willd. (FRESH-WATER CORD-GRASS.) Culm rather 

 slender (2 -6 high) ; leaves narrow (2 -4 long, ' or less wide below), taper- 

 ing to a very slender point, keeled, flat, but quickly involute in drying, smooth 

 except the margins ; spikes 5 - 20, scattered, spreading ; rhachis rough on the 

 margins ; glumes awn-pointed, especially the upper, the lower equalling the lower 

 palet, whose strong rough-hispid midrib abruptly terminates below the membra- 

 nous apex. (Trachynbtia cynosuroides, Michx. L/imnetis, Pers.) Banks of 

 rivers and lakes, especially northward. Aug. Glumes strongly serrulate-hispid 

 on the keel ; the awn of the upper one about ' long. Palets somewhat unequal. 

 Certainly distinct from the next, to which, in strictness, the Linntean name 

 belongs. 



2. S. polystachya, Willd., Muhl. (SALT KEED-GRASS.) Culm tall and 

 stout (4 -9 high, often 1' in diameter near the base); leaves broad (^' to 1'), 

 roughish underneath, as well as the margins; spikes 20 50, forming a dense oblong 

 raceme (purplish) ; glumes barely mucronate, the lower half the length of the equal 

 palets, of Avhich the rough-hispid midrib of the lower one reaches to the apex. 



