ZOOLOGY AND BOTANY. MICKOSCOPY, ETC. 295 



different ecological conditions ; (2) to indicate concisely the develop- 

 ment of the leaves with a view to deriving a practical and rational 

 method of measuring the cells : (3) to estimate the systematic value of 

 the organs of the gametophyte. The author made a great number of 

 cultures with a view to testing the variability of the species under the 

 influence of such external conditions as light, heat, moisture, soil ; and 

 gives his results. In the matter of cell-measurement he discusses such 

 questions as whether the mere lumen should be measured, or whether 

 half the thickness of the cell-wall should be included at each end of 

 the diameter ; whether extreme cells, the largest and the smallest, should 

 be measured, or whether the average of the cells measured provides a 

 better character ; whether both the length and the width of the cells 

 should be taken, or the width only ; which cells ought to be measured. 

 In summing up, the author finds it advisable to employ the characters 

 of the sporogonium for -defining the family Cephaloziellacea?, while the 

 yenera2kXQ based upon the characters of the involucre and the propagula ; 

 the suh-genera and groups of species upon the leaf -lobes, the insertion of 

 the leaves, the amphigastria, the involucre, the inflorescence ; the species 

 and varieties upon the size of the cells, the papillae, the inflorescence, 

 the width of the lobes, the denticulation of the perigonial leaves, the 

 perianth (whether cladocarpous or acrocarpous), the lateral and dorsal 

 denticulation of the leaves, etc. A. G. 



New or Rare British Hepatics.— W. E. Nicholson {Journ. of 

 i>o/., 1921, 59, 202-4). Critical notes on the following species: — 

 Riccia Hueheneriana Lindenb., discovered at Horsted Keynes, Sussex, 

 and compared . with R. pseudo-frostii. Gephalozia spinifi.ora Schiffn., 

 gathered on Ambersham Common, Sussex, and issued* in Schiffner's 

 exsiccatffi as G. macrostachya Kaal., but now shown to be distinct from 

 the latter species, and therefore constituting an addition to the British 

 Flora. Crphaloziella elachista (Jack) Schiffn. var. spinigera (Lindb.) 

 K. MiilL, discovered with well-developed perianths in the bogs of 

 Ashdown Forest : the affinities with G. striatuJa, etc., are discussed. 



A. G. 



Contribution to a Knowledge of the HepaticsB of Kataiiga 

 (Belgian Cong-o).— G. Gola {Nuov. Giorn. Bot. Italiaiio, 1920, 27, 

 24-4-O0, 1 pi.). An account of a small collection of hepatics collected 

 on the bark of shrubs on the pastoral savannah near Elizabethvillc by 

 Dr. Bovone. Descriptions of nine new species are given, belonging 

 chiefly to the genera FJagiochila and Lejeunea. A. G. 



Influence of Water on submerged Mosses. -A. HAMMERScmrm 

 i^Mit. Bayer. Bot. GeselL, 1917, 3, ;;95-4:Ul ; see also Bot. GentraJbl, 

 1918, 138, 313). The upper part of Hypnum aduncum Hedw. { = H. 

 Kneiftii Schimp.), when submerged, becomes H. pseadojiviians, showing 

 that the latter is merely the waterform of H. aduncum. H.-fl.uiians 

 and H. subtiiersum stand in similar relation. H. rotse is the waterform 

 of H. exannulatwn, ?ind H.fallaz is the springwater form of H.filicinum. 

 Springwater acts very strongly on H. commutatum either by lengthening 

 the leaves or by a reduction ; while rushing water causes also a strength- 

 ening of the midrib. Hyyroamblysteyium crassinervium is probably 



