fOTAMOGKTON. TETRANDRIA. TETRAGYNIA. 197 



leaves about a line broad, membranaceous, approximate, and 

 appearing somewhat distichous. 

 Hab. In similar situations with the preceding. August. 



4. P. diversifolium Bart.: upper leaves floating, ellipti- 

 cal, petiolate, 5-nerved; inferior ones filiform ; spike axillary, 

 almost sessile, few-flowered. Bart. Comp. F/. Phil. I. p. 

 96. P. setaceurn Pursh F/. I. p. 120. P. capiUaceuni 

 Poir. Enc. Supp. IV. p. 333 ? Roem.(^ Schul t. HI. p. 

 .507. 



Stems numerous, branched, filiform. Upper leaves about three- 

 fourths of an inch long, and a line and a half broad, obtuse or 

 a little acute, distinctly 5-nerved ; base attenuated into a very- 

 slender petiole about as long as the leaves. Spikes 4 — 6- 

 flowered, on very short peduncles. 



Hab. In ponds and small streams. Plentiful in the pine bar- 

 rens of New-Jersey. June Plaintield, Massachusetts. Por^ 

 ter. Litchfield, Connecticut. Brace. 



A very delicate and handsome species, quite distinct from 

 the P. setaceurn of Europe. 



* * Leaves <xll submersed. 



5. P. perfoliatum L.: leaves amplexicaul, cordate, ovate, 

 IV ill d. Spec. I. p. 713. Smith Fl. Brit. I. p. 194. Eng. 

 JBof. t. 168. M ick. Fl. I. ^. lOl. P ur s h FI. l.p. \20. 

 Muhl, Cat. p. 17. Roem. k Schult. III. p. 307. 



Stem dichotomous. Leaves an inch or more in length, fcubpel- 

 lucid, closely embracing the stem at the base, and thus ap- 

 pearing perfoliate. Spike on a short peduncle, oblong, few- 

 flowered. 



Hab. In rivers and lakes ; common. Abundant in the Hudson 

 above the Highlands. August. 



6. P. lucens L. : leaves ovate-lanceolate, petiolate. 

 Willd. Spec. I. p. 714. Smith Ft. Brit. I. p. 194. Eng. 

 Bot.t. 376. Mich. FL I. p. ]0l. P ur s h Fl. \. p. \20. 

 Muhl. Cat. 17. Roem.ir Schult. III. p. 509. 



Stem long, branched, terete. Leaves 2 — 3 inches long, 1 inch 

 broad, acuminate, abruptly contracted at the base into a short 

 petiole, pellucid and reticulated. Peduncle elongated, (some- 

 times 6 inches long.) Spike cylindrical, many-flowered, 

 greenish-brown. 



Hab. In rivers and lakes ; rarer than the preceding species. 

 August. 



The North-American plant, Mic hau x remarks, is four 

 times smaller than the European, and the leaves not acuminate j 

 but I have not been able to find any difi"crence between them, 

 having specimens of the latter from England ?.nd Germany. 



