356 On American Species of the Genus Potamogeton. ■ 



Leaves all membranaceous, pale green, in (3 and y often fusces- 

 cent, linear, sensibly a little tapering upwards, and very shortly 

 so at the base, which is more or less distinctly biglandulose, 

 sessile ; — in « broader, obtusish, submucronate, oftener 5-nerv- 

 ed, with here and there a few scattered, more or less conspicu- 

 ous veins, which are most numerous in the highest, 1-2 inches 

 long by 4 of a line wide to a line in width ;■ — in § narrower, 

 more or less acute or acuminate and often cuspidate, 3-nerved, 

 the lateral nerves commonly inconspicuous, the space next the 

 midrib on each side more or less widely reticulate-cellulose, 



nearly veinless, 1J-2 inches long by J to f of a line wide; — in 

 y very narrow, acute or cuspidate above, the lateral nerves sub- 

 obsolete, veinless, shorter than in the other varieties. Stipules 

 large for the plants, delicate, pellucid, acute, at length lacerate. 

 Peduncles subeompressed, or nearly terete, a little thickened near 

 the spike, half an inch to 1£ inches long. Spikes more or less 

 cylindrical and whorled, interrupted, few-flowered, about half an 

 inch long; or, in 3 and / oftener crowded-capituliform. Nutlets 

 obliquely elliptical, subtricarinate, a little rostrate with the short 

 style, the back rounded-carinate slightly curved downward below 

 the apparent base, a sunken line on each side indicating the lat- 

 eral keels, the sides convex and gently sloping to the obtusish 

 face. Exocarp thin. Putamen thick, not hard. Seed eonvolute- 

 uncinate. This species is probably rather common in the North- 

 ern States. The American plants here referred to «, and ft agree 

 generally with my European specimens, and, as well as )', are 

 always recognizable by the rounded-carinate fruit. The variety 

 « closely resembles P. obtusifolius, an European species not yet 

 observed in this country, but is distinguished from it by its fruit, 

 and its 5-nerved leaves. 



Potamogeton pauciflorus, (Pursh): caule compresso ramo- 



sissimo ; foliis omnibus submersis membranaceis saturate viridibus 



anguste linearibus versus apicem sensim levissime basique bre-" 



vissime attenuatis sessilibus, apice acutis, 3-nervibus, nervis late- 



ralibus plus minus obsoletis, subvenosis; stipulis linguiformibus 



membranaceis teneris acutis; pedunculis brevibus compressis sub 



spica incrassatis spicis paucifloris capitatis subglobosis floriferis 



plus minus reversis, subduplo longioribus; fructibus recentibus 



subcompressis, dorso vel acute carinato sinuato-dentato oblique 



ellipticis vel lato-alato dentato subrotundo-obovatis, mucronato- 



rostratis, carinis lateralibus obsoletis, lateribns convexiusculis in 



faciem vel acutam vel earinatam declivibus. P. pau< fonts, 



Pursh FL e Chamiss. Barton Comp. FL Phil 1, p. 97. Ell 



St I, p. 222. Bigel Host. edit. 2, p. 63. Torr. ! FL U.S., 



p. 198. Chamiss. in Linncea. 2, p. 176, /. iv, p. 7. Kth. 



Enum. 3. p. 136. Beck Bot n p. 386. A. Or J Man. BoL, 



p. 457. Wood Bot. p. 526. P. gramineus, Michx. FL 1, 





