GRAMIXF..-E. (GRASS FAMILY.) 551 



divaricate, the lateral a little shorter than the middle one. — Virginia to Illinois, 

 and south westward. — Resembles small forms of the next. 



* * Awns united below into one, jointed ivith the apex of the palea: root annual. 



7. A. tuberculosa, 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 palea ; 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. 



16. SPARTINA, Schreber. Cord or Marsh Grass. 



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

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

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

 upper one much larger and exceeding the pointless and awnless palese, 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 o-napTivr], a cord, such as was made from 

 the bark of the Spartium, or Broom). 



* Spikelets compactly imbricated, rough-hispid on the keels: spikes more or less pedun- 



c/ed : culm and leaves rigid. 



1. S. cynosuroides, Willd. (Fresh-water Cord-Grass.) Culm 

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

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

 smooth except the margins ; spikes 5-14, scattered, spreading ; rhachis rough on 

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

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

 nous apex. (Trachynotia cynosuroides, Michx. Limnetis, Pers.) — Banks of 

 rivers and lakes through the interior, chiefly northward. Aug. — Spikes 2' -3' 

 long, straw-color. Glumes strongly serrulate-hispid on the keel ; the awn of the 

 upper one about 4/ long. Palea? somewhat unequal. — Certainly distinct from 

 the next, to which, in strictness, the Linnasan name belongs. 



2. S. polystachya, Willd., Muhl. (Salt Reed-Grass.) Culm tall 

 and stoict (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 

 palete, of which the rough-hispid midrib of the lower one reaches to the apex. 

 (Trachynotia polystachya, Michx. Dactylis cynosuroides, L.l in part, excl. 

 var.) — Salt or brackish marshes, within tide-water, especially southward. 



3. S. juucea, Willd. (Rush Salt-Grass.) Culms low (l°-2° high) 

 and slender; leaves narrow and rush-like, strongly involute, very smooth ; spikes 1-5, 

 on veiy short peduncles; the rhachis smooth ; glumes acute, the lower scarcely J 

 the length of the upper, not half the length of the lower palea. (Dactyls pa- 



