606 RECORD OF CURRENT RESEARCHES RELATING TO 



indicate that the Pligeosporese form a connecting link between tho 

 Zygosporeee and the Oosporea^. 



New Parasitic Alga.* — J. Kiihn has made the interesting disco- 

 very of an alga parasitic on the leaves of Arisarum vulgare (^Arum 

 Arlsarum) in the neighbourhood of Mentone and Nice. 



On otherwise normally developed leaves, specks were observed of 

 a roundish form, usually 10 or 12 millimetres in diameter, having 

 all the ajipearance of a parasitic fungus. Closer examination showed, 

 however, that the parasite consists of filaments always densely filled 

 with chlorophyll-grains ; in fact, that it is an alga nearly allied to 

 Vaucheria, and propagating in the same way, by the whole contents 

 of the cell breaking up into microgonidia, which remain for a con- 

 siderable period in a dormant condition. The author proposes for it 

 the name Phyllosiplion Arisari. He considers the discovery to be of 

 considerable interest from a systematic point of view, in forming a con- 

 necting link between the two sections of Sachs's subclass Coeloblastas, 

 those containing chlorophyll, viz. the Siphonete, and those destitute 

 of chlorophyll, the Saprolegniepe and Peronosporefe. It is a very 

 interesting addition to the small number at present known of truly 

 parasitic algae. 



Siphonocladaceae, a new Group of Green Algae.t — In a descriptive 

 article of the green alga? of the Gulf of Athens, T. Schmitz describes 

 a new species and genus under the name Sijjhonodadiis Wilbergi, which 

 he proposes as the type of a new group, the Siphonedadacece, to 

 include a number of genera of hitherto imcertain affinity, viz. 

 Chcetomorpha, Cladophora, Pitliopliora, Microdictijon, Anadyomene, 

 Valonia, Botrydium, and Struvea. 



The characters of the proposed group are to be found in the 

 structure of the thallus, but still more in that of the protoj)lasmic 

 cell-contents. The parietal primordial utricle is sometimes, though 

 not always, furnished with a number of reticulate and anastomosing 

 strings which run across the cell-cavity ; imbedded in this are a number 

 of small, flat chlorophyll-grains of irregular angular form and very 

 variable size, which multiply by bipartition. The parietal protoplasm 

 invariably contains a number of nuclei, scarcely distinguishable by 

 their refractive power, but only by the application of reagents. The 

 vitality of the protoplasm shows a remarkable power of resistance to 

 external influences. As the mode of reproduction is not at present 

 known in all the genera, and presents a variety of differences where 

 it is known, it is probable that the group may hereafter be broken up 

 into several subdivisions. In Cladophora and Botrydium non-sexual 

 macrozoospores and sexual microzoospores are described ; in ChMo- 

 morpJia, Anadyomene, Valonia, and Siphonodadas, only zoospores of 

 one kind ; in Microdidyon and Pithophora no organs of the kind 

 have yet been detected. The bodies described by Wittrock in the 

 last genus as "spores," Schmitz believes to be gemmai of peculiar 

 form , 



* ' SB. Nat. Gesell. Halle,' 1878; see 'Bot. Zeit.,' xxxvii. (1879) p. 322. 

 t Ibid., Nov. 30, 1878 ; see ' Bot. Zeit.,' xxxvii. (1879) p. 167. 



