372 95. POTAMOGETONACB^. 



veina, the upper often almost sessile and nearly orbicular, sope- 

 times slightly cuspidate. .Petioles plane-concave above. Spikes 

 long, cylindrical. Anth.-cells nearly parallel. Sep. ovate. Fr. 

 greenishj f lin. long. — Stagnant peaty water. P. VI. VII. 



E. S. I. 



4. -P. rufes'cens (Schrad.) ; submersed I. lanceolate narrowed 

 at both ends subsessile membranous pellucid entire not apiculate 

 with chainlike network near the midrib, floating 1. subcoriaceous 

 obovate blunt narrowed into a short petiole, stip. without wings, 

 fr. acutely keeled, peduncle equal.— ^. B. 1286. R. vii. 32. P. 

 fiuitans Sm. — St. simple. Upper 1. alone slightly coriaceous, 



often tinged with purple, longer than their stalks ; submersed 

 1. all nearly, if not quite, sessile. Sep. "transversely oval." — 

 Ditches and slow streams. P. VII. E. S. I. 



5. P, lanceoldtus (Sm.) ; submersed 1. linear-lanceolate sessile 

 entire not apiculate with chainlike network near the midrib, float- 

 ing 1. subcoriaceous elliptic-lanceolate shortly stalked, stip. 

 linear-lanceolate acute uppermost broader, peduncles equal. — 

 U. B. 1985 (not P.). — ^St. very slender, slightly branched. 

 Floating 1. not always present with the flowers. Uppermost 

 stip. apparently with 2 stronger dorsal ribs. Vr. unknown. — 

 Streams, rare. Between Bodafon ajid Lligwy, Anglesea ^ P. 

 VII. VIII. E. 



6. P. sparganiifdlius (Laest. !) ; submersed I. linear narrowed 

 at both ends very long sessile entire not apiculate with many 

 parallel veins next the midrib, floating 1. subcoriaceous lanceolate 

 long-stalked, stip. very long blunt not winged, fr. "acutely 

 keeled " (Fr.), ped. rather slender not clavate. — Sy. E. B. 1403. 

 — St. very slender, slightly branched. Floating 1. often wanting. 

 Submersed 1. sometimes 2 ft. long, very narrow, few-veined 

 with additional parallel veins closely placed next the midrib. 

 L. very much longer than those of P. lanceolattts and without 

 the chainlike network, beautifully green when well dried. 

 Exactly the plant of Fries, H. N. xiv. 75. — In the river at 

 Ma'am, Oo. Gralway. I. 



7. P. salidfolius (Wolfg.) ; submersed i narrowly strapshaped 

 sesale narrowed at both ends entire not apiculate, floating 1. 

 subcomceous elliptic long-stalked, stip. long bluntish not 

 winged, fr. obliquely obovate 3-keeled. — P. lonchites Tuck. Sy. 

 E. v. 1404. — St. slightly branched. Submersed 1. with a few 

 additional parallel veins next midvein, subsessile. Floating 1. 



' I think that the Irish plants which I called P. lanceolatu^ may 

 be forms of P. polygonifolims as Mr. Syme supposes ; and probably 

 this plant from Anglesea ie the same as T. variifolius There. 



