TETRAXDRIA TETRAGVNIA 115 



faff, %t teeth and apex terminating in sharp spines; petioles one fourth of an 

 fnch kng. Flotrers in small loose fascicles, or solitary, pedunculate, scattered 

 along the lower part of the young branches ; pedicels with minute bracts at base. 

 Calyx 'segment s acute, ciliate. Corolla yellowish white ; petals ovate-oblong, ob- 

 utse, fi'igbtly cohering at base, (sometimes 5 or 6). Stamens shorter than the co- 

 rollas 'sometimes 5 or C). Berries roundish-ovoid, smooth, red when mature, per- 

 sistent. 



Hob. Woodlands : Mica-slate hills: Brandy wine: rare, Fl. June. Pr. Sept. 



Obs. This handsome evergreen is very rare, and of small growth, with us. I 

 liave Oflly met with one or two specimens. Seven or eight additional specie* art 

 8>nnd i Q the U. States,— chiefly in the South. 



84. POTAMOGETON. L. Mitt. Gen. 186. 

 (Gre*k, Polamos,* River, and Geitan, a Neighbor; from its place of growth, j 



Flo-wets on a Bpadix arising from a spathe. Calyx of 4 sepals. CV 

 rollu 9. Jlnthers subsessilc. Ovaries 4, becoming 4 compressed and 

 somewhat cochleate nuts. 



Herbaceous aquatics : floating or submersed ; leaves alternate or opposite, with 

 parallel nerves ; flowers on axillary or terminal spadices, arising from rncmbran- 

 aus spajhes. Sat. Ord. 258. Limit. Fluviales. 



+ Upper leaves floating. 



1. P. frATAKS, Li Lower leaves submersed, linear, membranaceous, 

 often iftmpcrfect ; upper ones floating, elliptic, coriaceous, on long pe- 

 tioles. Beck ! Hot. p. 385. 



P. fluitftns \ of .Authors. 



SwiMlfiKO Potamooetow. Vulgo — Floating Pond weed. 



Root Perennial. Stem 9 to IS inches long (varying with the depth of water). 

 Floating leaves '2. to 3 inches loner, and an inch to an inch and half broad, often op- 

 posite, o r nearly s:>, oblong-oval, generally acute at each end (often cordate at base, 

 Torr.) y many-nerved, on petioles 3 to 6 inches or more in length; submersed leaves 



2 to 6 inches l<»ner, narrow, sometimes wanting, or nothing more than a petiole. 

 Spadix fmerged, about an inch long, on an axillary peduncle 2 to 3 inches long, 

 sheathed at base by a membranous bract like spathe. Sejxds suborbicular, eon- 

 cave, du.i green. Nuts with a short oblique beak, 



Hab. P<>ols, and slow-flowing streams: frequent. Fl. July. Fr. Sept. 



Obs. This has always passed for P. nutans, here / but it agrees better with tht 

 description of P. Jtuitans, of the books. The latter, however, may be only a vari- 

 ety of P. nutans,— as has been suggested by several distinguished Botanists. 



j* f Leaves all submersed. 



2. P. perfoliatum, L. Leaves sessile, amplcxicaul, oblong-ovate, 

 somewhat cordate at base ; spadix short. Beck, Bot. p. 386. 



P. crispum. Florul. Cestr. p. 23. Not of Linn, ajid others. 



Perfoliate Potamogeton. 



Whole plant under water. Root perennial. Stems numerous from the root, I te 



3 feet long, branching somewhat dichotomously. Leaves about an inch long and 

 half an iiich wide, closely embracing the stem, alternate, oblong-ovate, obtuse, or 

 something rather acute, entire, slightly waving on the margin, 3-nerved, er el* 



