ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 341 



plants which present hermaphrodite characters. In the present paper 

 they show that these hermaphrodite products of apospory are absolutely 

 sterile. The reason for this sterility is at present inexplicable. Histo- 

 logical research has given no clue. The authors have also experimented 

 with monoicous mosses, and report that the gonophytes of aposporic 

 origin (they are diploid) are fertile, and the resulting sporophyte is 

 tetraploid. Further, in the tetraploid sporophytes thus formed, sporo- 

 genesis produces spores enclosing chromosomes twice as numerous as in 

 normal generation. Finally, on comparing normal gonophytes with 

 diploid and tetraploid gonophytes, it was found that the cells and 

 nuclei of the latter are larger proportionally to the number of their 

 chromosomes. 



Proper Value of a Species.* — F. Renauld discusses at some length 

 the notion of the species from the point of view of nomenclature. The 

 species, being one of the bases of nomenclature, ought, so far as is 

 possible, to have a fixed value. Much inconvenience is caused by the 

 admission into systematic botany of species of such different values as 

 emanate from the opposed camps of the "splitters" and "lumpers." 

 Renauld has himself long oscillated between the two camps during his 

 prolonged study of the polymorphic forms of the European Harjndia ; 

 during a study of the variations of the North American mosses as com- 

 pared with European ; and when monographing the mosses of the East 

 African islands. He discusses the merits of species in a large sense and 

 in a narrow sense, and shows that in countries where the forms are well- 

 known and can be studied in the living state, the most satisfactory 

 solution is to be found in the employment of subspecies rather than of 

 small species, but that for the flora of a remote region where little is 

 known of the plants, it is better to adopt the system of making pro- 

 visional species and to note carefully their nearest affinities. 



Cohesion-mechanism of Moss-lea ves.f — C. Steinbrinck continues 

 his discussion with W. Lorch about the cohesion-mechanism of moss- 

 leaves, and contends that cohesion-mechanism plays the principal part 

 in the distortions which moss-leaves undergo when they become desiccated. 

 He discusses three questions in connection with the cause and manner 

 of these cell-distortions. 



British Mosses. J— The Moss Exchange Club issues its fifteenth 

 annual report containing the customary long lists of exchange-specimens 

 of mosses and hepatics, often with critical notes by one or more members 

 of the Club. The Census Hepatic Catalogue being nearly exhausted, a 

 new and more complete edition is contemplated. 



Lancashire Mosses. § — J. A. Wheldon gives an account of a collection 

 of mosses put together by the late F. P. Marrat about sixty years ago. 

 Marrat collected round Liverpool. His specimens are of value as throw- 

 ing light upon doubtful or obscure records of South Lancashire mosses. 



J. A. Wheldon and A. Wilson || record the finding of Grimmia 



* Journ. de Bot., xxii. (1909) pp. 135-46. 



t Ber. Deutsch. Bot. Gesell., xxviii. (1910) pp. 19-30 (figs.). 



% York : Coultas andVolans, 1910, pp. 329-60. 



§ Journ. o.: Bot., xlviii. (1910) pp. 102-5. 



|| Tom. cit., p. 111. 



