POTAMOGETON MACVICARII: A NEW HYBRID 107 



On these special specimens I seem to have made no 

 remark, at that time accepting the name without comment. 



In August 1906 Dr. Graebner of Berlin paid me a visit 

 in connection with his work on the genus for Engler's 

 " Natiirl. Pflanzenfamilien " ; and as a result I have gone care- 

 fully over many hundred specimens both of British and 

 foreign examples to assist him in his work. On this sheet 

 of specimens coming under examination, I at once saw they 

 differed from pr&longus in many ways. To examine at once 

 my series from all over its area of distribution was a natural 

 result, with the conclusion that there was nothing among 

 them similar. Turning to Mr. Macvicar's letter accompany- 

 ing the specimens, he writes, " I send you a long narrow- 

 leaved P. prcelongus from Ardnamurchan. It is the longest- 

 leaved form I have seen." In this same letter, speaking of 

 the loch in which the specimens were gathered, he remarks, 

 " The only other Potainogetons in the loch which could be 

 seen were P. natans and P. polygonifolius, but of course 

 there may be others." 



Consulting many Continental and British floras, I can 

 find no reference to any other condition in the species than 

 " semiamplexicaul leaves" (Fries 1 remarks "Folia semper 

 semiamplexicantia, nulla petiolata, basi subovata ") ; except 

 that Chamisso, in Linn. 2, p. 192 (1827), in the description 

 says, " ex ovato sensim attenuata." 



In the original description of the species by Wulfen 2 he 

 says, " Fol. . . ., omnino sessilia ex ovata semiamplexicauli 

 basi," and, later on, adds, " sed sessilia." 



Mr. Macvicar has lately kindly sent me his collection of 

 specimens of the genus for Moidart, etc., and among them 

 are specimens of polygonifolius with submersed elongate 

 leaves very like some of the young growths of the present 

 plant. I may here say how necessary it is to study this 

 genus in all its aspects, especially the young spring and 

 autumnal growths ; Mr. Fryer, who has done this more than 

 any other botanist, has shown how needful it is to the full 

 understanding of the many and difficult problems the genus 



1 "Nov. Fl. Suec." 42 (1828). 



2 F. X. Wulfen. ' Plant, nov. descriptiones,' in Rcemers " Arch, ftir die 

 Botanik." iii. 331 (1805). 



