438 95. POTAMOGETONACE^. 



almost sessile and nearly orbicular, sometimes slightly cuspidate. 

 Petioles plane-concave above. Spikes long, cylindrical. Antli.- 

 celis nearly parallel. Sep. ovate. Fr. greenish, f lin. long. 

 IP. Billupsii (Fryer) J. ofS. xxxi. (1893) p. 353, t. 337-8 is P. coloratus 

 X Zizii.'] Stagnant peaty water. P. VI. VII. E. S. I. 



6. P. alpinus (Balb.) ; 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. E. B. 1286. E. vii. 32. 

 P. rufescens (Schrad.) ed. viii. P. jhdtans Sm. St. simple. 

 Upper 1. alone slightly coiiaceous, 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.) ; submersed 1. linear-lanceolate sessile 

 entire acute not apiculate with chainlike network near 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. J. of B. xix. t. 217 (not JR.). St. very slender, slightly 

 branched. Floating 1. not always present with the flowers. No 

 fruit even on Sept. 28. [Mr. Fryer considers this P. heterophyllous 

 X pusillus.'] By the bridge at Penrhos Llio-wy, An^lesea. Bur- 

 well Fen, Cam'br. Clare. Galway. P. VII. IX. E. I. 



8. P. sparganifolius (Laest. !) ; submersed I. linear narrowed at 

 both ends very long sessile entire not apiculate with many 

 parallel veins next the midrib, floating 1. subcoriaceous lanceo- 

 late long stalked, stip. very long blunt not winged, fr. " acutel} 7 

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

 1403. P. Kirkii (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. 7o. 

 [Mr. Fryer does not consider this the plant of Laest. but probably P. na- 

 tans X polygonifolius.~] In the river at Ma'am, Co. Galway. I. 



9. P. oraminifolius (Fr.) ; submersed L narrowly strapshaped 

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

 subcoriaceous elliptic long-stalked, stip. long bluritish not 

 winged, f r, obliquely obovate 3-keeled. Sy. E, B. 1404, P. sali- 



