680 Bryophyten. 



Zustimmung, in anderen Widerspruch erfahren. Aber hiervon 

 abgesehen, wird die in dieser Publikation verkörperte Bewältigung 

 eines durch Jahrzehnte kritisch gesichteten Materials, womit, wenn 

 wir nicht irren, der Verf. den Abschluss seiner Lebensarbeit liefern 

 wollte, als ein bedeutendes Verdienst allgemein gewürdigt werden. 



L. Loeske (Berlin). 



Skene, M., The Acidity of Sphagimm and itsrelationto 

 Chalk and Mineral Salts. (Ann. Bot. XXIX. W. CXIII. p. 

 65—87. 1915.) 



Investigations on this subject (Weber, Gräbner, Haglund, 

 etc.) are briefly reviewed, with a fuller consideration to the work 

 of Baumann and Gully, and the criticisms of Tacke and others 

 on the nature of "humus acids". The author's investigations are an 

 extension of Paul's (1908), and deal criticallj^ with the var3'ing 

 resistance of species of Sphagna to mineral Solutions. Some impro- 

 vements are introduced into methods for estimating acidit\\ As 

 regards the localisation of the acid Compounds, the results contirm 

 the view that colloids in the cellwalls, rather than the living Con- 

 tents, are mainly concerned. The acid reaction is also demonstrated 

 in various Mosses and in leaves of moorland plants but some nega- 

 tive results were obtained. The tests on Sphagna extend over 12 

 species from N. E. Scotland, and several samples (2 — 7) of each 

 were examined by a calcium acetate method. The results tabulated 

 Support Paul's conclusion that species from poor habitats require 

 the highest acidity to obtain the necessary amount of bases. The 

 table also shows the amount of saturated acid, equivalent to the 

 amount of absorbed base; the different species because of their 

 different acidity are able to hold approximately the same amount of 

 base in reserve. Cultures in Solutions of calcium carbonate and other 

 mineral Solutions were carried on with 3 species. The author's con- 

 clusions include: There is a Variation in acidity and in sensitiveness 

 to chalk between the different species of Sphagnuin\ there is an 

 indirect correlation between acidity and sensitiveness; Sphagna 

 thrive in acid Solutions, chalk and alkalies are injurious because 

 alkaline; mineral Solutions are generally harmless, but may be 

 ecoloafically harmful; Sphagna utilise the bases held absorbed by 

 the cell-walls. W. G. Smith. 



Torka, V., Bryotheca Posnaniensis. Lieferung IT. N" 51 — 100. 

 (Verlag O. Weigel, Leipzig, 1914). 



In der neuen Serie dieses Exsikkatenwerkes werden u. a. aus- 

 gegeben: Amblyodon dealbatus, Bvachythecium ciirtiim \ . attenuatum 

 Roth, Meesia triquetra, Phascum curvicolhim, Ph. mitraefovme 

 Warnst., Philonoti^ Arnellii und calcarea, Physcomitrella patens v. 

 hicasiana. Ricciella Hübeneviana in der vom Herausgeber entdeckten 

 v. natan<. Torka, Steveodon repiilis, Sphagtnim obtiisiim v. riparioides 

 W,, Drepanocladus intennedius und vernicosus u. a. m. Auch die 

 übrigen Arten gehören in den Rahmen der Moosvegetation des 

 nordostdeutschen Flachlandes, und alles ist reichlich ausgeebeng. 



L. Loeske (Berlin). 



"Wapnstorf, C, Ueber die vegetative Vermehrung des 



