MAEINE ALGiE. 



I.-PH^OPHYCB.E AND FLORIDEiE. 



By Antony Gepp, M.A., F.L.S., and Ethel S. Gepp. 

 (Four Plates.) 



Though the number of species, apart from the Corallinaceae, collected within the 

 Antarctic Circle by the British Antarctic Expedition is but small, and the specimens 

 themselves are mostly fragmentary and badly preserved, yet among them are included 

 some interesting novelties. Some of these were briefly described in the Journal of 

 Botany, April, 1905, pp. 105-109, with the alg« of the Scottish National Antarctic 

 Expedition. One of them, which is common to both collections, Gracilaria simplex 

 {Leptosarca simplex), is unfortunately only represented in the present collection by 

 dried and crushed material ; and though it is markedly distinguished by its 

 vegetative structure, the details of this could not be worked out until the clue was 

 given us by some pickled material in the ' Scotia ' collection. A second species of 

 Gracilaria, G. dumontioides, comes from Cape Adare, and is extremely interestino- 

 from the point of view of distribution, for it appears to be the same as an Arctic 

 species which was collected in 1853 by Dr. David Lyall in the very northerly latitude 

 of Northumberland Sound, and was named Halosaccion dumontioides by Harvey, but 

 never described ; for he had dried sterile material only, in whi.ch, through the collapse 

 of the inner cells, the structure is obscured. 



Magnificent specimens of Lessonia grandifolia were brought back by the 

 ' Discovery,' the largest lamina attaining a length of 24 ' feet before it was dried. 

 Infant plants of the same species (about one inch long) were found attached to 

 Desmarestia harveyana. We erroneously recorded (Journal of Botany, loc. cit.) 

 L. grandifolia as having been collected in the South Orkneys by the Scottish 

 Expedition. Though we found the two plants so much alike in external habit, we 

 have been compelled, after a further examination of their minute structure, to separate 

 them specifically. The ' Scotia ' plant will be found below, described under the name 

 L. simulans. The occurrence of two such large new species of algse is a rather 

 startling indication of how much may yet remain to be investigated in the South Polar 

 marine flora. 



vor,. III. 2 L 



