POTAMOGETON. 439 



cifolius, ed. viii. (not Wolfg.) 1 St. slightly branched. Sub- 

 mersed 1. with a few additional parallel veins next mid vein, 

 subsessile. Floating 1. often wanting. Fed. long, slightly 

 thickened upwards. In river Boyne near Navan. [R. Lawne, 

 Killorglin. Pidley Fen, Hunts.] P. E. I. 



10. P. heterophi/l' lus (Schreb.) ; submersed I. lanceolate nar- 

 rowed at both ends sessile minutely denticulate and apicidate, 

 floating 1. subcoriaceous elliptic stalked, stip. broadly lanceolate 

 blunt with 2 stout prominent ribs, lower ones linear-lanceolate, 

 fr. blunt on the back, peduncle thicker than the stem swelling 

 upwards. E. B. 1285. R. vii. 41 43. P. yraminem Fries, 

 not Linn. St. much branched below. Submersed 1. wavy. 

 Lower stip. without the two strong ribs and equally veined, 

 upper ones widely spreading. Dry fr. slightly marked with 3 

 ridges on the back. Ponds and ditches. P. VI. VII. E. S. I. 



11. P. nitens (Web.); submersed I. lanceolate rounded below 

 and half clasping wavy at the edge, floating 1. ' coriaceous 

 elliptic stalked," stipules equally veined, (dry) fr. keeled, ped. 

 swelling upwards. J2. vii. 34. Sy. E. B. 1407. J. ofB. ii. t. 23. 

 St. rather wavy, branched below. Subm. 1. pellucid, often 

 recurved ; upper 1. often not coriaceous. Upper stip. large, per- 

 sistent, nearly J a 3 long as the peduncle. Dry fr. with 3 ridges 

 on the back. [Mr. Fryer considers this a series of hybrids P. gramini- 

 folius X perfoliatus, P. heterophyllus X perfoliatus, and P. Zizii X 

 perfoUatus, and writes " rarely fruiting, with 1 or 2 drupelets on a spike, 

 probably resulting from a chance fertilization by allied species."] Lakes 

 near Brandon Mountain, Kerry (P. curvifolius Hartin.). Loch 

 Ascoo-, Bute. River Tay, Perth. Coltfield, Elgin, &c. 

 P. VII. VIII. E. S. I. 



12. P. falcdtus (Fryer) ; submersed 1. sessile elliptical strap-shaped 

 often not quite symmetrical with somewhat rounded base, the 

 upper amplexicaul, the margin entire slightly undulated, floating 1. 

 stalked elliptic mucronate coriaceous, stip. herbaceous persistent upper 

 broad, fr. small rhomboidal-ovoid acutely keeled with distinct lateral 

 ridges, ped. thicker than the st. scarcely swollen upwards usually shorter 

 than the 1. J". ofB. xxvii. (1889) p. 65, t. 286. St. branched from near 

 the base. Fen ditches, Hunts. P. VI. VII. E. 



13. P. var'ians (Fryer) ; submersed 1. sessile or shortly stalked narrowly 

 lanceolate usually flat, floating 1. stalked oval or more or less spathulate 

 apiculate coriaceous, stip. herbaceous persistent narrow bluntish, fr. small 

 nearly circular flattened very acutely keeled with prominent lateral ridges, 

 beak short, ped. slightly thicker than the st. not thickened upwards from 



1 Mr. Ley's plant from Sellack which according to the Author's MS. 

 is probably P. salicifolius, is considered by Mr. Fryer to be a hybrid of 

 unknown origin. H. & J. G. 



