A MONOGRAPH OF THE BRITISH LICHENS 171 



elusion among lichens of plants formerly regarded as algae {Conno- 

 gonium, Bacodium), partly to the discovery in recent times of 

 genera new to Britain (e. g. Gongylia). The subdivisions bring 

 the book into line with Continental text-hooks, and cannot fail to 

 be acceptable to students who have had to grapple hitherto with 

 the unwieldy mass of incongruous species "lumped" together 

 under such genera, for instance, as Lecidea and Verrucaria in the 

 older manuals. It is, of course, quite possible to go to the other 

 extreme by the process known as " splitting," but while this has 

 been avoided, confusion is obviated by careful and systematic 

 reference to modern synonyms. As stated in the introduction to 

 this volume, " more importance is assigned in these days to the 

 microscopic character of the apothecia than was allowed by 

 Nylander and Crombie in their scheme of classification." Eelying 

 on such natural distinctions, Miss Smith adopts 11 of the genera 

 into which Lecidea has been divided, with three subgenera of the 

 restricted genus— Psora, Biatora, Mycoblastus. Of the old genus 

 Graphis, as described in Leighton's Lichen-Flora of Great Britain 

 and L-eland, only four species are retained under that generic 

 name, the rest being assigned to Phceographis and Graphina. We 

 venture to think that the author might have gone a step further, 

 and adopted Aulacographa for G. elegans and the allied species 

 with a furrowed proper margin to the fruit. Out of Verrucaria of 

 the old lichenologists, 13 genera are taken, which yet leaves 48 

 species in the type-genus. 



A systematic and modern revision of natural affinities is in- 

 dicated by the removal in the scheme of this volume of the orders 

 Gladoniacece and Gyrophoracece to the subtribe Lecideei, and of 

 Dirinacea and Boccellacece to the Graphidei. Strigula, Endo- 

 coccus, and Myriangium, regarded by Crombie and other lichen- 

 ologists of his time as belonging to lichens (see vol. i.), are here 

 relegated to fungi pure and simple. This fact is mentioned by 

 Miss Smith (p. 263), though the names are not to be found in the 

 index, whilst Agyrium and Odontotrema, presumably also fungi 

 (vol. i. p. 15), are left without reference. 



Since in these and other details the systematic arrangement 

 preferred by Miss Smith differs rather widely from that jpro- 

 pounded by Crombie in the introduction to vol. i., we are inclined 

 to think that a new Conspectus Generum, following the lines 

 adopted in this volume, might have been desirable. The meagre 

 glossary of technical terms prefixed to vol. i. has expanded in this 

 to one that is copious as well as clear, while the admirable index 

 to the entire work will be especially hailed as a boon by those 

 students whose good resolutions of indexing the previous volume 

 for themselves have never been carried out. After the small 

 figures of microscopic details in the first part of the work, the 

 fifty-nine full-page illustrations of the second part come as a 

 pleasing surprise. These plates, ranging from a view of the plant 

 as it appears in situ to higlily magnified points of structure, are 

 attractive and, so far as we have had an opportunity of testing 

 them, accurate. 



