16 THE JOUKNAL OF EOTAiNY 



The lake is 1620 feet altitude lying under Y Foel Fras, 3091 ft. 

 alt., and all around are mountains. ^Iv friend the late E. Straker, 

 who went there at my request, considered that the lake " had been 

 formed hj the damming-up of the valley by the remains of an 

 ancient glacier ; the moraine is composed of large sharp rectangular 

 blocks of stone, partly covered by bog " : at a quarter of a mile 

 from tlie lake the ground by the stream out of it has fallen 

 to 113-4 feet. It is a case of isolation exactly similar to that of 

 Sal mo ni<j)'opinnis (the black-finned trout), which also occurs in 

 these isolated Welsh Lakes. I had the plant growing many years 

 along with P. alpimts and pr(sloii(/tis : Fryer suggested it might be 

 a per/olid fun, poI^(/onifoIh(s, or prcelouf/us hj^brid, and remarked 

 "if alpintcs, where are the roots of this, and where are the traces of 

 its peculiar winter-buds ? " 



1 have gathered the P. Grijpthii (cultivated) at all seasons 

 of the year from March to October: in March the leaves are 

 petioled, and very translucent, quite different from alpinus or 

 prcelonr/us, which grew by its side in the same tank. 



I hope at some future time to discuss P. kehvigeii Wolfg., but 

 this is not a British species. 



P. PR-ELOxaus Wulf. (p. 250). Sweden to S. Lapland (Berlin) ; 

 Noricay to 69° 58' n. lat. {Korman) ; Finland to 69° 30' n. lat. 

 {Euwald) ; Scotland to Shetlands {Beehy). 



This is one of the least variable species, both here and elsewdiere ; 

 we do not have var. latifolius Alpers (leaves subrotund), or var. 

 elegans Tis. (leaves 30 cm. long x 20 mm. wide). 



P. PEEFOLIATUS L. (p. 251). Sivedeii to S. Lapland (Berlin); 

 J^^orivay to 70° n. lat. {Norman); Finland to 69° 31' n. lat. 

 {Wainio) ; Scotland to Shetland {Beehy). Leaves very variable 

 from almost round to 12 cm. long X 3 cm. wide. A form like the 

 former has been described as a species (P. hiipleuroides Fernald). 



P. CE1SPU8 L. (p. 58). Sweden and Norway to Gestricia at 

 60° 30' n. lat. ; Finland, Aland isles only ; Scotland and Orkney 

 and Outer Hebrides. The largest forms I have seen from Britain 

 are from Kinghorn Loch, Fife {W. Syme), leaves 90 mm. x 15 mm., 

 und Sidcot, Somerset ( W. F. Miller), 85 mm. X 15 mm. 



This does not \iuy much with us ; curiously enough, Hagstrom 

 .does not mention P. scrratus Hudson as a synonym. So far as 

 one can judge from named specimens in herbaria (I have not seen a 

 type) the var. planifoliies G. F. W. Meyer, Chloris Hanov. 623 

 (1836), is the same form. The author retains E. F. Linton's 

 var. cornufus. 



*P. Bexnettii Fryer (p. 63). This he regards as crisjmsx 

 jpusillus, not criapusxohtusifolius as suggested by Fryer. 



*P. LiNTONi Fryer. This is regarded by Hagstrom as P. crispus x 

 Fricsii, bat is only mentioned in his index. 1 have it from Shere, 

 >Surrey, C. E. Salmon, 1912. On a specimen from Ireland (Canal 

 below Calloron, Co. Fermanagh, 1892, Praeger) Fryer remarks 

 {in Hit.)' "This is my Bennettii,'" but I think it should rather 

 be referred to '' Lintoniy I sent it to him suggesting "P. crispus X 

 ohtusifolius ? " 



