332 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Thallophyta. 



Alg-ae. 



Points of Algological Nomenclature.* — R. Chodat publishes notes 

 on the nomenclature of certain genera, as to which he differs from other 

 authors. He first deals with the question as to whether Wille is right 

 in considering Sphccrocystis Chod. a synonym of Glwococcus A. Braun. 

 The author considers there is no justification for this course, since 

 Glfxococcus is a palmelloid condition of some alga unknown, while 

 Sphcerocystis is characterised by its colonies of microscopical, free- 

 swimming cells, which are quite spherical. The latter plant has been 

 often found, while no one but "Wille has ever been able to recognise 

 Glaococcus. In the second note, the author discusses SphcereUa and 

 Ghlamydomonas, and shows that though SphcereUa nivalis scarcely 

 differs from a Chlamydomonas, still the name SphcereUa should be 

 maintained. S. lacustris should be S. Wranyelii Sommerfelt. In the 

 next note, the differences between Pteromonas nivalis Chod. and Astasia 

 nivalis Shuttlew. are pointed out. Finally, the new genus Ghionaster 

 Wille is stated to be a synonym of the fungus Gerasterias nivalis Bohlin, 

 which is the same as Tetracladium De Wildeniann. 



Colour of Algae and of Water.f — N. Gaidukov summarises the 

 work of former writers on the relation between the colour of algse and 

 the rays of light which reach them at their various depths. Hehas 

 himself experimented on Oscillatoria sancta and 0. caldariorum, and 

 finds that the colour of these species alters under the influence of dif- 

 ferently coloured lights, and he compares his results and conclusions 

 with those of other writers on the subject. The depth of the water 

 through which the sun's rays have to pass affects the quality of the light 

 which reaches the plants, and the colour of the alga accommodates itself 

 .accordingly. Water, however, varies in colour according to the season, 

 the condition of the sky, etc. ; and irrespective of these variations there 

 are many other influences which affect the distribution in depth, and the 

 colour of the alga?. But, speaking generally, the most important 

 factor in the distribution in depth, and the colour of alga?, is the 

 quality of the sunlight — the source of energy. In fact, the author 

 sums up the whole question as follows : In the process of photosyn- 

 thesis, therelitions between certain rays and the work performed by 

 them can only be quantitative. The view concerning the harmful 

 or beneficial effect of this or that ray of light on the processes of photo- 

 synthesis is without justification, as is also the view that chlorophyll is 

 the only assimilative colouring matter in those chromophyll-containing 

 algee growing in deep water ; and both these views are contrary to the 

 great natural law — the conservation of energy. 



Sexual Reproduction in Ceratium.J — E. Zederbauer has observed 

 for the first time sexual reproduction in the Peridineee. In Ceratium 

 hirundinella, a fresh-water form, two individuals become fixed together 

 by a mass of slime ; from each there then grows out of the longitudinal 



* Bull. Herb. Boiss., iv. (1934) pp. 233-40. 



t Hedwigi;i. xliii. (1904) pp. 96-118. 



J Bcr. Deutsch. But. Ges., xxii. (1904) pp. 1-8 (1 pi.). 



