35G REPORT OF DEPARTMENT OF BOTANY, BRIT. MUS., 1895. 



Althongh that brook is the source of P. natansm this locality, no plants 

 of F. iinitans have been found in it, in spite of repeated and careful 

 examination. Again, no floods have occurred recently such as could 

 have washed roots or seeds from the upland water into the new pit. 



I think the question of the reappearance of P. naUms itself, 

 letting alone fluiUms for the moment, in this restricted locality is 

 only to be explained in one way — by the rootstock having survived 

 in the soil, made damp by winter floods, for many years without 

 having been able to push up stems or leaves ; certainly none have 

 been seen during the fifteen years I have visited the spot, which has 

 been perfectly dry in summer and grazed over by cattle. 



Now if we allow that a strong rootstock of P. natans managed to 

 survive in the dried-up mud and clay for some years, we only add 

 another instance to many which are familiar to all fen-men of the 

 persistent vitality of buried roots of water-plants. 



To return to P. jiuitans .-—the fact of most interest to me is that 

 it remains quite unaltered in both localities, it is exactly as it was four- 

 teen years ago, no variation whatever has taken place ; and as I have 

 never yet seen forms of P. fluitnns from any two localities, however 

 near to each other, exactly alike, I can come to only one conclusion 

 • — that the reappearance of P. Jiuitans in the original locality is due 

 to a long-buried rootstock. Probably when the locality at Ramsey 

 was constantly under water, as it was prior to 1848, the original 

 seedling x P. jhdtans covered a considerable space, as the trans- 

 planted roots now do at Warboys. 



In habit of growth P. jiuitans keeps very distinct from my 

 P. crassifulius, which I still think a hybrid with Zizii as one parent 

 instead of lurens. Where Zizii does not grow we find only the 

 typical P. Jiuitans! * 



EFFORT OF DEPARTMENT OF BOTANY, BRITISH MUSEUM, ISOa.f 

 By George Murray, F.R.S.Ed. 



The collections have been enriched duriug the year by several 

 especially noteworthy additions. 



Mr. Arthur Lister has added to his previous gifts the further one 

 of 832 microscope shdes of Mycetozoa and 397 herbarium specimens, 

 as well as 112 exhibition specimens and 36 coloured drawings by 

 Miss Gulielma Lister to illustrate the British representatives of this 

 group. The latter series have been placed in a table-case in the 

 gallery. 



A collection of nearly 8000 drawings of British Fungi by Mr. 

 Edwin Wheeler, of great botanical value, has been generously pre- 

 sented by Messrs. Edwin and Henry Wheeler. The drawings are 

 of particular importance as accurate records of the colour characters 



* Since the above was written, rootstocks of both species have been found 

 (August 27th) under conditions continning the view advocated. 



[t This was accidentally omitted from our last year's volume ; we print it 

 now in order that the series may not be incomplete. — En. Journ. Bot.] 



