The Scottish Naturalist. 27 



July 10th. — Lunan Burn. 

 P. nit ens Web. 



var. latifolius Tis., not Fieber ; fide Bennett. 



A form with broader leaves than the normal nitens ; the lower 

 sub-cordate and half-clasping. 



There are two fine beds of this rare plant in the Lunan Burn, a 

 little way below Marlee Mill. 



Note. — The Lunan Burn drains the chain of lochs in the 

 Stormont district between Blairgowrie and Dunkeld, and falls into 

 the Isla. 



July nth. — River Isla. 

 P. nitens Web. 



There is a fine bed of this rare Potamogeton, some distance 

 below the mouth of the Lunan Burn. 



Aug. 1 st. — Loch Ben-a-chally. 

 P. rnfesce?is Schreb. 



Near the head of the loch, I gathered an interesting form of this 

 plant, with narrower leaves, and fruit much smaller and less acu- 

 minate than in the ordinary form. Mr. Bennett thinks it is pro- 

 bably Marsson's var. lacustris. Ovary, sometimes of five and even 

 six carpels — a thing of very rare occurrence in the genus, as Mr. 

 Bennett has justly observed. 



Aug. 7th. — Lunan Burn, in the lade above New Mill. 

 P. rufescens Schreb. 



Of this specimen Mr. Bennett says, " It is a good example of 

 P. spathulatus, Koch et Key, which Tiselius has shown is really 

 only a state of rufescens." 



Same date. — Marlee Loch. 

 P. pusillus, L. 



Sub-sp. Sturrockii Bennett. 



This is la grande trouvaille of the season. On sending speci- 

 mens to Mr. Bennett, he wrote : " As to the Marlee plant, it is 

 most interesting ; certainly not P. oblusifolius, M. et K., though I 

 have seen specimens of that from N. Germany, with peduncles 

 double the length of those as it usually occurs with us. I have 

 nothing like it from Europe or N. America." And in a letter of 

 recent date, he says : " I cannot let this pass as a variety. Many 

 French authors would call it a species. I quite think it should 

 bear sub-specific ra?ik, and as this is now adopted in the best Floras, 

 I think it would be well to so place it. We never shall, I suppose, 

 get over the old difficulty of how far one is a species and the other 

 not. It must remain a question of individual opinion to a great 



