5l6 NAIAD ACE AE 



First recorded by Mr. H, C. Watson in Britten's Contrib. 1871. 



2. Ock. Near South Hinksey, Not recently seen. 



3. Pang. Oare. Cold Ash Common. 



4. Kennet. Burghfield. Aldermaston. Ufton. Siielsmore Common. 



Greenham Common. Hampstead Marshall, &c. 



5. Loddon. Ascot, Wilkin, sub nom. P. naUins. Near Wokingham, 



Watson. Loddon river, Melvill. So common in the heathy district 

 as not to require localities. It also occurs in Virginia Water, 

 Bulmarsh, Bearwood, &c. 

 P. polygoni/olius is recorded for all the bordering counties except 

 E. Gloucestershire. 



P. fluita-ns, Roth Tent. Fl. Germ. i. 72 (1788). 



Keichb. Ic. Fl. Germ, et Helv. vii. 48, 49, f. 87, 88. Syme, E. B. ix. 

 63. Nyman, 681. 



Native. Lacustral. Rivers. Very local. P. July-August. 



First found, in Berkshire by the author in 1893. 



5. Loddon. Plentiful in the Loddon between Twyford and Loddon 

 Bridge. My attention was first called to it on a hot June day 

 b}' the beautiful green leaves, with very pellucid parenchyma, 

 which were growing in shallow water from a gravelly bottom in 

 the Loddon. It was then a new plant to me, and I could not 

 resist the pleasure ( f gathering it in situ, so I at once walked 

 into the stream and procured a good series of specimens. Subse- 

 quently I hired a boat at Loddon Bridge and then was able to 

 trace the plant for a considerable distance along the stream, not 

 only in shallow but in deep water, in very fine condition and 

 flowering freely. Mr. Fryer places it under P. fluitans, Roth., 

 but says it is not quite like any other /luitans in his herbarium. 

 My idea, when I gathered it, was that it was a hybrid, P. natans x 

 alpinus. 

 An interesting note on this species will be found in Journ. Bot. 



(1888) 273-8, by my friend Mr. A. Frj-er. 



Surrey is the only one of the bordering counties for which P. fluitans 



is recorded. 



P. coloratum, Hornem. in Fl. Dan. t. 1449 (i^iS)- 



P. plantagineus, Du-Croz ex Roem. et Schultes, Syst. iii. 504 (1818). 

 Top. Bot. 422. Syme, E. B. ix. 29, t. 1401. Nyman, 682. 

 Native. Lacustral. Pools of stagnant water in boggy places. Very 



local. P. June-August. 

 First found in Berkshire by the author, and recorded as P. plantagineus 

 in the Journ. Bot. 362, 1886. 

 2. Ock. Abundant in Cothill Marsh, fruiting freelj', associated with 

 Chara hispida, Utricitlaria major, &c. 



