120 ON THE PHYSIOLOGY OF PLANTS. 



is sufficient to separate Comatricha ti/phoidcs (our old friend C. 

 Ujphuta) from C. Fersoonii, while apparently much more striking 

 differences, quite as constant, fail to keep Physarum IcucopJufHin 

 from blending with PJujsanim [TUmidoche) nutans. That species 

 var}' is to be expected, but the forms with which the present volume 

 has to do vary less than do many organisms of higher pretension. 

 This is the experience of most students of the group. While we 

 are considering the genus Physarum. we may note Physarum jwly- 

 morphuin. Eost., here made, as usual among the Physarums, to cover 

 a multitude of supposed synonyms. Tilmadoche f/yrocephala is 

 included, but not Physarum jiolycephahun Schw., which certainly, 

 according to description, is the same thing ; and if T. f/yrocephala 

 is P. polymorphum, then the Schweinitzian name has priority, and 

 the consolidated species should bear the name P.polyccphaJum Schw. 



The physiological part of Mr. Lister's work must not be over- 

 looked. This is found in the preface, where we have an interesting 

 account of his cultures and staining methods. Karyokinesis is 

 described as characterizing the plasmodia of many species. 



The plates which accompany the descriptions of the more 

 difificult species are all from water-colour drawings, and are re- 

 produced by photography. The water-coloured originals are fine, 

 as the writer hereof can personally testify ; but the best results by 

 photographic methods are not obtained from tinted drawings. 

 For collotype, zinc-etching, &c., nothing equals black on white. 

 This is apparent in Mr. Lister's work : species whose natural 

 colours are black and white are represented best. 



The whole appearance of the work, its convenience for the pur- 

 pose to wdiich it is directed, the great amount of conscientious labour 

 it evinces, are matters of sincerest congratulation alike to the dis- 

 tinguished author, to students of the subject who are everywhere to 

 become his pupils, and to the trustees of the noble institution 

 whose liberality presents such a volume to the scientific world. 



T. H. McBride. 



A Popular Treatise on the Physioloyy of Plants, for the use of 

 Gardeners, Sc. By Dr. Paul Sorauer. Translated by Prof. 

 F. E. Weiss, B. Sc, F.L.S. Longmans, 1895. Pp. x, 256 ; 

 33 figs. Price 9s. net. 



A LARGE number of very worthy botanists to whom plant 

 physiology, as commonly presented to them, has few attractions, 

 will find in this book an introduction to the subject of a pleasant 

 and satisfactory kind. It is designed for gardeners and students 

 of horticulture and agriculture, but it requires an elementary 

 knowledge of botany, chemistry, and physics, not commonly pos- 

 sessed by gardeners even in this enlightened time. So equipped, 

 however, the student may read the whole book without finding a 

 hard or dull page. It is very readable, and that is almost the 

 same thing as saying it is unique among treatises on plant 

 physiology. We have no wish to disparage well-known books on 

 plant physiology, readable enough to the admirably learned; but 



