I90 THE SCOTTISH BOTANICAL REVIEW 



A Monograph of thk British Desmidiace^. By W. and G. S. 

 West. Vol. iv. Ray Society, London, 1912. Pp. xiv+igi, 

 Plates 96-128. Price 25^. net. 



We are indeed glad to welcome the fourth volume of this masterly 

 work, containing as it does the completion of the exceedingly difificult 

 genus Cosmarium. No one who is not a student of this most complex 

 subject can appreciate the amount of knowledge and labour required 

 for the compilation of such a work, and the authors have conferred 

 an incalculable benefit upon students by the undertaking. 



Besides the completion of the genus Cosmarhwi, the genera 

 Xanthidiiirn and Arihrodesfjius are dealt with, and the genus Staur- 

 asfrum started, the first forty-one species being described and figured. 



The authors describe three new species (as well as many varieties), 

 viz. Xanf/iidium Orcadense, from a sphagnum bog in the Orkneys, 

 and which the authors in 1896 described as X. Robinsonianum, from 

 which it differs, however, " in its open sinus and in its more scattered 

 and more reduced spines, and the rounded and less evident central 

 protuberance"; Staurastrian pilosellujn, from Cornwall; and S. 

 i?iflatum, from W. Yorks. 



The authors' treatment of the genus Staiirastrum is worthy of note. 

 Attempts to split the genus upon natural principles having failed, 

 they group it in two divisions : 



Division I. Angles of semi-cells not produced into processes. 



Division II. Angles of semi-cells produced into processes. 



Each of these divisions, again, is divided into several sections. 

 This treatment seems in every way satisfactory. 



As in former volumes, the book contains plates of all species and 

 varieties described, while another valuable feature is an additional 

 bibliography which brings the literature up to date. 



Clare Island Survey. Part XIV. : Lichens. By Miss Annie 

 LoRRAiN Smith, F.L.S. Dublin: Hodges, Figgis & Co., 

 191 1. Price dd. 



The Report on the lichens of Clare Island made by Miss A. L. 

 Smith is of very great interest, as it is the work of an accomplished 

 lichenologist, who has quite recently completed the monograph of 

 British lichens commenced by the Rev. J. M. Crombie. Miss 

 Smith devotes six introductory pages to the geographical features of 

 Clare Island and district, the rocks, and the ecological factors, which 

 especially determine the distribution of these plants. The rocks are 

 covered by grass, moor, and bog, but are often " denuded of soil, and 

 lie exposed to sun and wind — ideal situations for lichens." In some 

 parts rock specimens abound, being " of a more or less alpine 

 character." Quartzite, typically barren, here yielded Rhizocarpon 

 ^eographicum, as elsewhere. Numerous corticolous species were 

 found in the woodlands. Previous work in this district had been 

 limited, and was mainly due to Larbalestier, who died only last year. 



