284 SUMMAKY OF CURRENT RESEARCHES RELATING- TO 



intermediates ; and the author considers that not the least interest in 

 the alga? groups lies in the fact that they offer us forms arrested in the 

 different stages of the evolution of generations ; and that these forms 

 indicate lines probably parallel to the evolution followed phylogentically 

 by forms of a higher type. He points out how little the lines of our 

 classification of the alga? follow the grouping founded on the facts of 

 alternation. These would compel us to split up Phasophycea?, and to 

 divide off the diatoms of benthos from those of plankton. Since, how- 

 ever, the whole use of classification is to form a practical guide, it would 

 be unwise to exaggerate the systematic importance of such characters as 

 alternation of generations and the conclusions arising from their study. 

 But they should be at least taken into account. And since, as the 

 author remarks, the algae are regarded as chaotic, why should not order 

 be introduced by following the clue offered by the alternation of gener- 

 ations ? This paper is a masterly exposition of the subject by a young 

 man of two-and-twenty, who shortly after writing it was killed in a 

 railway accident in the Alpes-Maritimes on his return from the yearly 

 manoeuvres. 



Fungi. 

 (By A. Lorrain Smith, F.L.S.) 



North African Laboulbeniaceae.* — Rene Maire gives descriptions of 

 some Laboulbenias observed by himself and by Picard in Africa, and he 

 has published a list of those recorded by Thaxter for the same region. 

 He gives two new varieties and a new species with detailed descriptions, 

 and with comparative and biological notes. 



Systematic Position of Microstroma and Helostroma.t — Rene 

 Maire calls attention to the confusion between these genera of Hypho- 

 mycetes. The name Fusidium Juylandis was first given to a fungus 

 which covers the leaves of the walnut with a white film. It was after- 

 wards changed to Microstroma. An allied species is frequent on leaves 

 of oak in our own country, known as Fusisporinm or Microstroma 

 {Helostroma) album. Maire has examined the latter and finds that a 

 stroma is formed within the tissue of the leaf ; the conidiophores 

 emerge through the ostiole and form conidia at the tips ; after these are 

 mature the stalk grows further and forms another head of spores, etc. 

 Maire finds that the two genera are identical and that they are not 

 Basidiomycetes. 



Observations on Phytophthora erythroseptica.J — It was in this 

 fungus that G. H. Pethybridge found the peculiar development of the 

 sexual organs already described. Similar processes have been discovered 

 in Phytophthora infestans, and in several other species. There are five 

 species known which belong to the restricted genus Phytophthora. The 



* Extr. Bull. Soc. Hist. Nat. Afrique du Nord, iv. (1912) 5 pp. (1 pi.). 



t Algiers (1913) 9 pp. 



\ Sci.Proc. Roy. Dublin Soc, xiv. (1914) pp. 179-97 (1 pi.). 



