352 
94. POTAMOGETONACEiE. 
obovate blunt narrowed into a short petiole, stip. without wings, 
fr. acutely keeled, peduncle equal. — E. B. 1286. i2. vii. 32. P. 
fiuitam Sm. — St. simple. Upper 1. alone slightly coriaceous, 
often tinged -wdth purple, longer than their stalks ; submersed 1. 
all nearly, if not quite, sessile. Sep. "transversely oval." — 
Ditches and slow streams. P. WL. E. 8. 1. 
5. P. lanceoldtus (Sm.) ; siibmersed I. linear-lanceolate sessile 
entire not apiculate with chainlikc network near the midrib, 
floating 1. subcoriaceous elliptic-lanceolate shortly stalked, stip. 
linear-lanceolate acute uppermost broader, fr , peduncles 
equal. — E. B. 1985 (not i?.). — St. very slender, slightly branched. 
Floating 1. not always present with the flowers. Uppermost 
stip. apparently with 2 stronger dorsal ribs. Fr. keeled with 
faint lateral ridges (stronger when dry). — Streams, rare. Be- 
tween Bodafon and Lligwy, Anglesea. Buttermere. Killamey. 
Antrim. P. VH. VTU. E. S. ? I. 
6. P. sparganiifoliics (Laest. !) ; submersed I. linear narrowed 
at both ends very long sessile entire not apiculate icith many 
parallel veins next the midrib, floating 1. subcoriaceous lanceolate 
long-stalked, stip. very long not winged, fr. " acutely keeled " 
(Fr. ). — St. veiy 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 umch longer than those o^ P. lanceolatus and 
without the chainlike network. Ped. very long, thick, equal. — 
Fries' plant from Lapland is certainly the same. — In the river 
at Ma'am, Galway. Mr. T. Kirk. River Boyne near Navan. 
Mr. JD. Moore. I. 
7. P. heterophyl'lm (Schreb.) ; siibmersed I. lanceolate narrowed 
at both ends sessile denticulate and apiculate, floating 1. subco- 
riaceous elliptic stalked, stip. broadly lanceolate blunt xmth 2 
stout prominent ribs, lower ones linear-lanceolate, fr. blunt on 
the back, peduncle thicker than the stem swelling upwards. — E. B. 
1285. It. vii. 41 — 43. P. graminem 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. — nitmis 
(Weber) has the submersed 1. rounded and clasping at their 
base.]— Ponds and ditches. P. VI. \TI. E. S. I. 
** L. all submersed, monbranous, lanceolate or broader ; 
stipules free. 
8. P. lucens (L.); I. pellucid oval or lanceolate stalked denti- 
culate and cuspidate, stip. witiged, fr. blunt on the back and 
slightly keeled when fresh, peduncle swelling upwards, spikes 
cylindrical densely flowered. — E. B. 37G. Ji. vii. 36. — All the 
