382 95. POTAMOGEIONACE^. 



'* L. aU submersed, membranmis, lanceolate or broader ; stipulei 

 free. 



10. P. Zizii (Roth.) ; 1. pellucid narrow-lanceolate-oblong cus- 

 pidate narrowed dotcmoards minutely denticulate near the end 

 wavt/, stip. long broad broadly and doubly keeled not winged, 

 " fr. like that of P. lucens,^' ped. swelling upwards, very long. — 

 J. of B. xvii. t. 204. — St. long much branched, lower 1. usually 

 recurved. Ped. 4 — 5 in. long, thicker than the stem. Spike 

 about 1 in. long. — Cauldshiels Loch, Melrose. P. VII. VIII. S. 



11. P. lucens (L.) ; I. pellucid oval or lanceolate stalked mi- 

 nutely denticulate and cuspidate, stip. winged, fr. blunt on the 

 back and slightly keeled when heAt, peduncle sivelling upwards, 

 spikes cylindrical densely flowered. — E. B. 376. R. vii. 36. — 

 All the stipules have two prominent wings on their back. Spikes 

 long, about equalling the peduncles. — A form (?) has been found 

 with ovate-lanceolate subacute subcoriaceous floating leaves 

 (var. coriacous Nolte ?) which looks difl^erent. Sometimes 

 (P. acuminatus Schum.) the midrib forms a long prominent 

 point. — Common in deepish water. P. VI. E. S. I. 



12. ?P. decip'iens (Nolte) ; I. pellucid oblong ronnded below not 

 hooded but blunt mucronate and wavy at the end entire sessile 

 or uppermost 1. sometimes subsessile, stip. not winged ', fr. 

 "like that of P. lucens," ped. equal. — /. of B. v. t. 61. P. vii. 

 35. — St. long, much branched. Ped. 1 — 2 in. long, thicker than 

 the stem. Spikes 1 — 2 in. long, dense. — Canal near Bath. 

 Navan Canal. P. VII. E. S. I. 



13. P. longif alius (Bab. not Gay) ; I. pellucid long-lanceolate 



narrowed below entire cuspidate, stip. wmged, fr , ped. 



long sivelling upwards, spikes with few rather whorled distant 

 flowers. — U. B. S. 2847. — St. long, slender. L. distant, not 

 denticulate, nearly sessile, with very short stalks. Stip. green, 

 lanceolate, with 2 narrow wings on the back. Ped. 6 — 8 in. 

 long, much thicker than the stem. Spike 1 in. long ; fl. rather 

 more whorled than as represented in B. B. S. Fr. unknown. — 

 Deep water. Found floating loose in Lough Corrib, Galway. 

 P. VIIL t 



14. P. prcelon'gus (Wulf ) ; I. pellucid oblong-lanceolate half- 

 clasping blunt and hooded at the end entire, stip. not winged, fr. 

 keeled on the back when fresh heeled or winged wlien dry, pe- 

 duncle very long equal, spikes many-flowered. — E. B. S. 2858. 

 P. vii. 33. — St. long, growing in deep water. L. with parallel 



■^ I cannot find the wings described by Syme ; nor did Mr. Baker. 

 J. ofB. V. 71. 



