1918-19.] BOTANICAL SOCIETY OF EDINBURGH 323 



detailed and excellent account is given of this species, 

 though he includes under it many names of which he has 

 not seen specimens. These are nearly all in the Berlin 

 herbarium, whence I had them many years ago, and made 

 drawings of them for reference. 



P. fragillinus, Hagst. — I am puzzled how the author 

 connects m}^ P. lucens, var. fioridaoius, with the Guatemala 

 plant which he names as above. I know that Dr. Morong 

 named this fragillinus as P. malaianus, Miq. The author 

 refers to Graebner, Das Pflanzenreich, Heft 31, 79 and 161 

 (1907), where no mention is made of the Guatemala plant 

 ■\N\\e,n floridamis is described. 



P. variifolius, Thore (France). — The author refers this 

 to P. natans x P. trichoides. Until this is produced by 

 cultivation I must say I cannot believe it. 



X P. G/imnplanii, Ar. Benn. (United States).— In answer 

 to the author's remarks, I say that this has submerged 

 leaves entire! They are 11 cm. long x 10 mm. wide, 

 7-nerved. The upper (floating) leaves are 6-8 cm. long x 

 11-15 mm. wide, obtuse. 



P. capensis, Scheele = "P. ScJnveinfurthii, Ar. Benn," — 

 But Scheele's name is only in the Bremen herbarium, and 

 only noted by me, so cannot stand. If this were allowed, 

 there are dozens in the Vienna and Berlin herbariums that 

 might be used. 



P. gramineus, L. (P. heterojjhyllus, Schreb.). — Dr. 

 Hagstrom gives no conspectus of the varieties, only a 

 running commentary on them. The difficulty is great, I 

 know, and perhaps he is wise, not having seen the series 

 in other herbaria. 



P. nitens, Weber. — The fullest and best study of this 

 species yet given. 



P. Oakesianus, Robbins (United States). — " The specimens 

 from Pine Plains, N.Y., leg. Hoysradt (hb. Stockholm), must 

 be considered the hybrid gramineus x natans!' Whatever 

 the Stockholm specimens are, mine from the same place 

 (ivifh good fruit) are certainly P. Oakesianus, Robbins. 

 Some error in labelling ? 



P. lucens, L. — Dr. Hagstrom suggests that the African 

 and other forms placed under this species need careful 

 revision, and I agree. 



