164 SUMMAEY OF CURRENT RESEARCHES RELATING TO 



devoted to the morphology of the genus, under the headings — Epidermis 

 and epidermal pores, Compact ventral tissue, Ventral scales, Rhizoids, 

 Eeceptacles, Sporophyte, Cupules. A. G. 



Noteworthy Lejeunese from Florida. — Alexander W. Evans 

 {American Journ. of Botany, 1918, 5, 131-50, figs.). Descriptions of 

 the following new species : — GoloUjeunea contractiloha, Lejmnea clado- 

 gyna, Euosmolejeunea parvula, PtycJwcoleus heterophylhis, with critical 

 notes on these and other species. A. G-. 



Notes on New England Hepaticae. XIII. — Alexander W. Evans 

 {Rhodora, 1916, 18, 74-85, 103-120, 1 pi. and figs.). A discussion of the 

 specific values of Scapania OaJcesii Aust. and ^S', pahidicola Loeske and 

 K. Miill. ; of certain little-known structural characteristics of PorelJa 

 pinnata L., with some remarks upon its synonyms ; also a critical 

 comparison of P. platyphylla (L.) Lindb., P. p)latyphyUoidea (Schwein.) 

 Lind., P. rivularis (Nees) Trevis. {Madotheca Cordseana (Hiiben.) 

 Dumort.), and their allies. A. Gr. 



Hepaticse of St. Croix, St. Jan, St. Thomas, and Tortola.— 

 Alexander W. Evans {Brooklyn Bot. Garden Memoirs, 1918, 1, 104-9). 

 An enumeration of twenty-one species collected in 1913, together with 

 notes on the only seven species that had previously been recorded. 



A. G. 



Illustrated Key to the Western Sphagnacese.— T. C. Frte {Bry- 

 ologist, 1918, 21, 37-48). An artificial key intended to facilitate the 

 identification of the species of Sphagnum found in the western States of 

 North America. It is abundantly supplied with figures to illustrate the 

 points of structure selected for discriminating the species. A. G. 



Acidity of Sphagnum and its Relation to Chalk and Mineral 

 Salts.— M. Skene {Ann. of Bot., 1915, 29, 65-87). -An account of 

 previous work and of the author's own investigations on the varying 

 resistance of different species of Sphagnum to mineral solutions. As to 

 the localization of the acid compounds, the view is confirmed that 

 colloids in the cell-walls, rather than the living contents, are mainly 

 concerned. Species in poor habitats require the highest acidity to obtain 

 the necessary amount of bases. The different species vary in acidity and 

 in sensitiveness to chalk. Sphagna thrive in acid solutions ; and it is the 

 alkalinity of chalk and alkalies that is injurious ; mineral solutions are 

 generally harmless. Sphagna utiUze the bases held absorbed by the cell- 

 walls. A. G. 



Sphagna and Mosses of Thuringen. — J. Roell {Hedwigia, 1915, 

 56, 1-176, 177-287, 1 table ; see also Bot. CentralbJatt, 1915, 128, 

 679-80). An exhaustive account of the bryological flora of Thuringen, 

 The introduction describes the historic development of the moss system 

 and the share of the author in it, with a justification of his views of 

 nomenclature, and arguments against varieties based on colour. His 

 views in the polemic with C. Warnstorf are defended. In the special 



