310 POTAMOGETONACEiE. [Potamogeton. 



OEDER LXXVni.— POTAMOGETONACE^. 



POTAMOGETON Linn. 



1. P. natans (Linn.) — Floating Pond-weed. 



Districts 1 2 3 4 5 6 7 8 9 10 11 12 



Lat. 51°-56°- Throughout Lreland. 



Type in Great Britain, British. 



Ponds, ditches, lakes, rivers, &c. ; common. Fl. June, 

 July. 



2. P. polygonifolius (Pourr.) — Oblong- leaved Pond-weed. 

 P. ohlongibs (Viv.) Brit Flor., P. natans var. Bentham. 

 Districts 123456789- 11 12 

 Lat. 51°-56°. Throughout Ireland. 



Type in Great Britain, British, 



Ditches, streams, and boggy places ; common. Fl. June 

 to August. 



The commonest, probably, of all the pond weeds, and 

 especially abundant on the large bogs,^both in ditches and 

 bog-holes, also on damp ground. Very variable, according 

 to the kind of situation in which it grows. 



3. P. plantagineus (Ducr.) — Plantain-leaved Pond-weed. 

 P. natans var. Bentham. 



Districts 12-456789-- 12 



Lat. 51°-56°- Throughout Ireland, probably. 



Type in Great Britain, English, inclining to Germanic. 



Ditches in peaty ground ; rather rare. Fl. June, July. 



1. Near Bantry ; C. G. B. 1 and 2. Not unfrequent on 

 bogs near Cork; /. G — 4. Ditches on the Murrough of 

 Wicklow, and other places in Wicklow ; D. M. — 5. Plentiful 

 in a ditch near the thirteenth lock south of the Grand Canal ! 

 Kildare ; Mr. J. Douglas. Common in ditches on the bogs 

 among the Dublin Mountains ; D. M. — 6. In ditches in the 

 bog at KOmacduagh, Galway ; A. G. M. Near Portumna, 

 Galway; D. M. — 7. In the County West-Meath, near 

 MuUingar, &c. ; D. M. — 8. Near Galway ; Prof. Melville, 

 Connemara; D. M. Eoundstone; Mr. T. Kirk. — 9. Bog 



