438 
95. POTAMOGETONACE^. 
Petioles plane-concave above. Spikes long, cylindrical. Anth.- 
cells nearly parallel. Sep. ovate. Fr. greenish, | lin. long. 
\_P. Billupsii (Fryer) J. of B. xxxi. (1893) p. 353, t. 337-8 is P. coloratvsxang-usti- 
foiius.] — Stagnant peaty water. P. VI. VII. E. S. I. 
6. P. alpmns (Ba.\h. em. Aschers.) ; submersed h lanceolate 
narrowed at both ends subsessile membranous pellucid entire not 
a.jnculate \\\th. chainlike network near the midrib, floating 1. 
subcoriaceous, obovate blunt narrowed into a short petiole, stip. 
without wings, fr. acutely keeled, peduncle equal. — E. B. 1286. 
E. vii. 32. P. rufescens (Schrad.). P.Jluitans 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. 
7. P. lanceoldtus(Sm.) ; sM&TOersecZ 1. linear-lanceolate sessile 
entire acute not apiculate with chainlike networkn&ax the midrib, 
floating 1. subcoriaceous elliptic-lanceolate shortly stalked, stip. 
almost subulate uppermost broader with 2 dorsal elevated ribs, 
peduncles equal from uppermost floating opposite leaves. — E. B. 
1985. .7. of B. xix. t. 217 (not ^.).— St. very slender, slightly 
branched. Floating 1. not always present with the flowers. Ko 
fruit even on Sept. 28. [llrFiyerconsidersthisP. hetcTopliyllufxpusillui.'^ 
— By the bridge at Penrhos Lligwy, Anglesea. Burwell Fen, 
Cambr. Clare, Galway. P. VII.— IX. E. L 
8. P. sparganifdlitis (L&est. ! sec. Bab.) ; submersed I. linear 
narrowed at both ends very long sessile entire not apiculate irith 
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. — Si/. 
E. B. 1403. P. KirUi (Syme).— 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. lanceolatus and without the chainlike network, 
beautifully green when well dried. Exactly the plant of Fries, 
H. N. xii. 75. [Mr Fryer does uot consider this the plant of Laest. but 
probably P. natans y polygonijoUuf .'\ — In the river at Ma'am, Co. 
Galway. I. 
9. P. graminifolius (Fryer) ; submersed I. narrowly strap- 
shaped sessile narrowed at both ends entire not apiculate, float- 
ing 1. subcoriaceous elliptic long-stalked, stip. long bluntish not 
winged, fr. obliquely obovate 3-keeled. — Sy. E. B. 1404. P. sali- 
