8 tJlOCBEDlNGS OF TH15 



louiul ill Uoueriiig j)laiits juid only in small trees ; but Ontes 

 excelsa absorbs aluiiiina Iroiii tiie soil in large quantities, as shown 

 by analysis of the ash. Occasionally the amount taken up is 

 excessive, in which case the excess is deposited in cavities as a 

 basic uluminiiim succinate. 



]n reply to iSir tSulney llarmer, F.ll.S., Dr. lieiidle stated tluit 

 this deposit was characteristic of all specimens of this species. 



Dr. E. Marion Dklf gave an account of research on Mucrocysiis 

 by Miss M. M. Micukll and herself. After describing the dis- 

 tribution of tlie alga, the authors reviewed recent accounts of it, 

 and slio\\ed lantern-slides in explanation. 



The fertile fronds are completely submerged, smootli, dichoto- 

 niously brunciied, and usually borne on 8j)ecial shoots. They bear 

 sori on both sides of the frond. Exceptional cases were described 

 of discontinuous sori occurring in the grooves of fronds with 

 wrinkled surface and borne on the long swimming shoots, and 

 usually without a swim bhulder at the base. 



The zoospores do not appear to have been previously described. 

 Material brought from the shore in the morning, and examined 

 in the laboratory in the evening, showed swarming zoospores; the 

 next morning swimming actively, and more slowly. 



Cultui"es were made from the material in the following way : — 

 About two hours after gathering, the alga was placed in a covered 

 glass dish, with a few cover-slips at the bottom, and then sea- 

 water was added. The piece was removed the next day, and 

 10 days later all the zoospores had come to rest, but showing no 

 sign of germination. Five weeks afterwards short filaments of 

 two dift'ereiit sizes w'ei'e observed, comparable with the male and 

 female j^ametophytes in Laminariaiere reported by Sauvageau and 

 Lloyd Williams. Two montlis later young stages of the sporophyte 

 were visible on the cover-glasses, a thick-walled empty cell always 

 being at the base of the sporopliyte, probably the emjjty oogonial 

 wall after the escape of the oospore. No sign of the antheridial 

 cells had been noticed. The discovery of the filaments developed 

 from the zoospures and the subsequent growth of the sporophytes 

 from filaments bring it into line with other members of the same 

 family. 



The authors consider that the species occurring at the Cape is 

 Macrocijstis amjxstifoUa, Bory, from its rhizonie-iike attachments. 



A discussion followed, the [)articipants being Miss A. L. kSniith, 

 Sir W. A. Herdman, Dr. E. li. Gates, Mr. A. D. Cotton, and 

 Mr. J. Burtt-Davy, Dr. E. M. Delf replying. 



The next paper was by Mr. J. L. Chaworth Musters, 

 entitled "The Flora of Jan Mayen Island," with lantern-slides 

 (communicated by Dr. W. Eushton Parker, F.L.S.). 



The flora of Jan Mayen may be divided into four main groups : 

 the floras of the sea-shore, of the bird-cliffs, of sheltered j)laces 

 in the " tundi-a," and the mountain flora. The most luxuriant 



