ALGJE. 263 



spondence with Prof. Reinke, he has extracted the ad- 

 mission " that had he known of the Kilkee plant [i.e., 

 P. hibernicwii\, he would have hesitated before founding 

 the genus Pogotrichum" . Prof. Johnson himself comes to 

 the conclusion : " Thus I am led to believe that the two 

 genera, Litosiphon and Pogotrickum, are one and the same, 

 and ought to be united, and that L. Laminaricz and P. 

 hibernicum, if not one species, are very closely allied". 

 This is a very diffident attitude towards the genus he has 

 just been adding to, and phycologists who read Prof. John- 

 son's detailed reasons will regret that he has not had the 

 courage of his opinions to take "a short way with" Pogo- 

 trickum after disabling it. 



Miss Barton has, with much industry and care, brought 

 together the records of seaweeds from the Cape (4), and 

 with the help of collections made by Messrs. Boodle, Scott 

 Elliot, Tyson and others, principally in the British Museum, 

 very largely increased these records. The list does not 

 claim to be more than provisional, and to be inclusive rather 

 than exclusive in its tendency — very wisely in the present 

 state of our knowledge — but it furnishes material for an 

 interesting, if short, essay on the geographical relations of 

 the Cape marine flora. There is a table of detailed com- 

 parisons of the Cape seaweeds with those of Australia, of 

 Western Australia only, and of Kerguelen Land — and 

 another table of comparisons with the warm Atlantic and 

 the Indian Ocean. The latter table appears also in the 

 last paper cited under (5), of which, with the other papers 

 under the same number, it will become me to give only a 

 colourless abstract. The writer there uses the Cape totals 

 furnished by Miss Barton to make more effective his com- 

 parison between the marine floras of the warm Atlantic and 

 Indian Ocean. "We have here two tropical marine floras 

 cut off from each other by a permanent continental area, 

 and communicating only via the Cape. That these floras 

 have been periodically mingled at the epochs of warmer 

 climate at the Cape seems a reasonable conclusion with 

 regard to a group of such antiquity as the Algae, and the 

 proportions of species in common and genera in common 



