468 SUMMARY OF CURRENT RESEARCHES RELATING TO 



New Squamariacea.* — M. Foslie describes a new species which 

 he refers with certain donbt to Peyssonnelia, under the name of P. (?) 

 compacta. It forms part of Heydrich's Sporolithon mediterraneum, and 

 may also be identical with the same author's Polystrata dura from the 

 Island of Tami. It approaches very nearly to Peyssonnelia polymorpha 

 (Zan.), and may perhaps be a variety of that species ; but to decide this 

 point on sterile material is impossible, and the fruit of P. compacta is 

 still unknown. P. compacta has a crust-like thallus, up to 5 mm. thick, 

 very closely and firmly adherent to the substratum, though the author 

 has seen no rhizoids. It is very hard and stony, being encrusted with 

 carbonate of lime. In structure it approaches both Polystrata dura and 

 Peyssonnelia polymorpha, though the cells are a little larger than in the 

 former and a little smaller than in the latter. The plant occurs in the 

 Adriatic and Mediterranean. 



Cladostephus verticillatus.f — C. Sauvageau publishes the first part 

 of a detailed account of this plant, in which he treats of the structure, 

 growth, and ramification of the erect shoots (" pousses indefinies ") : a 

 further paper will deal with the branches, or " pousses definies." The 

 branching is never dichotomous, as has been supposed by some authors. 

 An erect stem, arising from a creeping thallus, produces at irregular 

 intervals similar shoots to itself, and these all bear branches arranged 

 verticillately. The ramification, taken as a whole, shows so much variety 

 that the author proposes to constitute a special group for Cladostephus 

 within Sphacelariaceaj, under the name of Polyblastas, parallel to Hemi- 

 blastaj and Holoblastas. The indefinite shoots ("pousses indefinies") 

 are plagioblastic ; the verticillate branches are hemiblastic, or meri- 

 blastic ; the branchlets of these are holoblastic ; and the fruit- bearing 

 shoots are microblastic. 



Distribution of Marine Algae. % — N. Svedelius has made some 

 interesting observations on the likeness that exists between the marine 

 vegetation of the West Indies, the Indian and the Pacific Oceans. He 

 deals with the work of other authors on this subject, and is himself of 

 opinion that the reason for the similarity in the three floras is to be 

 sought in the historical development of the distribution of land and 

 water on the borders of North and South America, where it is seen that 

 the Caribbean Sea is merely a creek, so to speak, of the Pacific Ocean, or 

 a strait connecting the two great oceans of the world. 



Nomenclature of Desmids, and other Algological Notes.§ — 0. 

 Nordstedt proposes that 18LS should be the starting point from which 

 to reckon the nomenclature of Desmids, and his reasons for this are 

 shown by an historical review of the work done on the group since 1810. 

 He lays down the following rules : (1) The nomenclature begins with 

 the "British Desmidiaceas," by Ralfs, in 1848. (2) The authors of 

 names given earlier, but accepted by Ralfs in " British Desmidiacese," 

 must always be quoted as such, unless the identification of the name in 



* Kgl. Norsk. Vidensk. Selsk., Skrift, 1905, No. 1, 9 pp. (fig. in text). 



f Act. Soc. Linn. Bordeaux, lxi. (1906) 26 pp. (figs in text). 



J Bot. Notiser, 1906, pp. 49-57. § Tom. cit., pp. 97-12 L 



