676 NAIADACE^ POBiMOQBTON 



sometimes winged, widely branching: leav'es'linear: mucronate or ahort- 

 poihted at the apex, 2-12 inches long, 1-2 lines wide, with 3 principal nerves 

 and many fine ones: stipules scarious, finely nerved, soon perishing: pe- 

 duncles lJ^-4 inches long: spike cylindric, about ]4 inch long, 12-15-flow- 

 ered : fruit obovoid with a broad base, about 2 lines long, 8-keeled on the 

 back, the lateral keels rather obscure, beaked' with a short recurved style : 

 embryo slightly incurved. In still or running water, Oregon to New Jersey 

 and New Brunswick : also in Europe. " 



P. foUosas Raf. Med. R6p.,.(n) y, 35-1. Stem^ flatjteaed, much bran- 

 ched, 1-3 feet long: leaves 1-2 inches long, )^-l line wide, acute, $■ nerved, 

 mostly glandular at base : stipules white, hyaline, obtuse to iicate, 6-10 

 lines long: peduncles'more or less clavate, erect, about 6 lines long : spikes 

 about 4-fiowered, fruit lenticTilar or nearly orbicular, about 1 line in diam- 

 eter, 3-keeled on the back,' the middle keel win^d and sinuate-dentate, 

 the face strongly angled or arched, sharp, often with a projecting tooth at 

 base : style apical. In ponds and streams, California to Brit. Columbia,, 

 and New Brunswick. 



Tar. Californiens Morong Bot. Gaz. x, 254. Stems stout and 

 bushy, strongly flattened. and sometimes winged, thickly clustered : leaves 

 smaller, with dilated midrib and frequently 5-nerved at base : peduncles 

 4-6 lines long, erect, clavate, flattened : spikes often ripening 12 strongly 

 marked fruits. Eastern Oregon to southern California. 



P. pnsillns L. Sp. 127. Stems flliform,- branching, 6-24 inches long: 

 leaves narrowly linear, 1-3 inches long, rarely a line wide, often nearly se- 

 taceous, 1-3-nerved, obtuse and mucronate or acute, biglandular and sessile ; 

 stipules obtuse, becoming setose: spike capitate or somewhat elongated 

 and open or interrupted, on slender flattened peduncles % to nearly 2 inch- 

 es long: fruit obliquelj' ellipsoidal, aibout a line long, 2-groovea on the 

 back or sometimes with 3 distinct keels : apex of the embryo slightly in- 

 curved and pointing obliquely downward. In ponds, Brit. Columbia to 

 California and across the continent : also in Europe. 



*■ *• Stipules united with the sheathing base of the leaf : spikes 



interrupted. 



P, pectinatns I,. Sp. 127. Stems ^lender, repeatedly branched, 1-3 

 feet long: leaves sfetaceous, attenuate to the apex, 1-nerved, 1-6 inches long, 

 often . Capillary and' nerveless: stipules half free, 6-12 lines long, thin: 

 sheaths scarious on the margins: peduncles flliform, 2-12 inches long,' 

 the flowers in verticils : fruit obliquely obovoid, with a broad thick shell, 

 1-2 lines long, plump on the sides : apex of the embryo pointing almost 

 'directly toward the basal end; In ponds and brackish or salt water, Brit, 

 Columbia to California and the Eastern States. 



P. Bobbinsil Oakes Hovey's Mag. vii, 180. Stems stout, widely bran- 

 cMng,. 2-4 feet long: leaves linear, 3-5 inches long, acute, finely many- 

 herved, crowded in 2 ranks, minutely serrulate, auriculate at the point of 

 attachment with the obtuse at length setose stipules : spikes usually sev- 

 eral,, on stout peduncles about an inch long, loose and more or less inter-' 

 rupted, about 6 lines long : fruit bblong-bbovatei nearly 2 lines long, keeled 

 with a broadish' wirig, acutely beaked: embryo stout, the apex pointing 

 a little inside 6i the basal end. . In ponds and lakes, Oregon to California 

 and the Atlantic States. 



Oedee CY SCHEUCHZERIACE.E Agardh 

 Theor. Syst. PL. '44. 



Marsh herbs with terete or semiterete leaves a,nd small 'flbw^' 

 ers in terminal spikes of racemes. Perianth 4-R-paftei3,' its 



