REPORT ON THE BOTANY OF THE ISLANDS OF THE SOUTHERN OCEAN. 181 



attenuato, deorsnm incrassato infra annulum crassum inobilera transversim flocculoso ; 

 laniellis leviter decurrentibus argillaceis. 



Tristan da Cdnha group. — Endemic. On trunks of Phylica nitida — Moseley. 



Pileus three inches or more across, convex, at first very smooth and even, at length 

 repeatedly areolate with a depressed wart on each division, margin turned up ; stem 

 excentric, attenuated upwards, thick and swollen below, solid, about two inches high, one 

 and a quarter inch or more thick in the centre ; ring thick, very soon detached, and 

 movable ; gills moderately broad, crowded, clay-coloured, decurrent, edge pale ; spores 

 oblong oblique, about '0003 inch long, but variable in size. 



Very nearly allied to Agaricus cajpistratvs, Cooke, but differs in several points, especially 

 in the incrassated stem. There is a misprint in Cooke's description of that species, the 

 figure being quite correct. 



ASCOMYOETES. 



Pyrenomycetes. 



Hypoxylon placentaeforme, Berkl. et Curt. 



Hypoxylon placeutceforme, Berkl. et Curt, in Journ. Linn. Soc. LonJ., x. p. 383, et Berkl. in Journ. 

 Linn. Soc. Lond., xv. p. 52. 



Tristan da Cunha. — On dead Phylica — Monday. 



Also in Cuba. 



Thouars (Escprisse Fl. Trist., p. 25) enumerates four fungi, namely — Merulius sp., 

 "hemispherical, laterally attached to the trunks of trees;" Agaricus sp., "a small species 

 laterally attached to the rotten trunks of trees ; " Sphcsria sp. (probably Hypoxylon 

 placentcefomw) ; and Peziza sp., " orbicular, purplish above, villous beneath." 



ALGJ1. 

 MELANOSPEKMEjE. 



Laminariace.e. 



Macrocystis pyrifera, K. A. Agardh. 



Macrocystis pyrifera, K. A. Agardh, Sp. Alg., i. p. 47 ; Kiitz., Sp. Alg. p. 582 ; Dickie in Journ. Linn. 



Soc. Lond., xiv. p. 384 ; Harv., Phyc. Austr., t. 202. 

 Fucus pyrifer, Linn. ; Thouars, Esquisse Fl. Trist., p. 25. 



Tristan da Cunha. Thouars; MacGillivray ; MoseUy. 



All round the Southern Ocean ; California, as far south as San Francisco; Unalaschka ; 

 Sitcha ; China. 



The distribution of this gigantic seaweed in the Southern and Pacific Oceans only is 

 noteworthy. 



