106 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



mistake : " The plant exposes as much surface as possible by having very 

 finely divided submerged leaves " (p. 98). But if you take any complete 

 leaf and cut out all the portions between the ribs and veins, you reduce, 

 not increase, the amount of surface. The fact really is (as Mr. MacCallum 

 has proved), the protoplasm is weakened by supersaturation, and cannot 

 make full-sized leaves under water ; but when the water is made denser 

 artificially by the addition of nutritive salts, the leaves then are com- 

 pletely formed though submerged. 



We repeat, the value of the book would have been greatly enhanced 

 if the author had introduced simple details of ecology. 



"Laboratory and Field Manual of Botany." By J. Y. Bergen and 

 B. M. Davis. 8vo., 257 pp. (Ginn, London, 1907.) 4s. Qcl 



This little book consists of three parts and a list of experiments. In 

 the preface the authors wisely insist that " the student is not to consider 

 himself as merely the corroborator of facts already ascertained ; he is to 

 interrogate the plant itself." In other words he is warned against 

 cramming. 



"Part I. consists mainly of studies on the Gross Anatomy and 

 Histology, &c. 



" Part II. consists of Type Studies outlining Evolution and Classifi- 

 cation. 



" Part III. is concerned with Laboratory and Field Studies, &c." 



By "field studies" the authors mean "ecology," which is the 

 application of all botanical study to the plant itself. This should be 

 the final goal of the student. The authors give instruction in the 

 field study of parasites, of carnivorous plants, of plant-protections, of 

 pollination, of vegetative propagation, of competition and invasion, and 

 of plant-successions. This is followed by "ecological classes," or the 

 study of hydrophytes, mesophytes, and xerophytes, &c. 



It would be a wise thing for our English writers of text and other 

 elementary books of botany to follow suit, for we need hardly say this 

 book is of American origin, the botanists of the United States being a 

 long way ahead of British teachers in the matter of ecology. It is an 

 excellent work. 



" Types of Floral Mechanism : a Selection of Diagrams and 

 Descriptions of Common Flowers arranged as an introduction to the 

 systematic study of Angiosperms." By A. H. Church, M.A., D.Sc. 

 Part I. : Types i. xii. (January to April). 4to., 211 pp. (Clarendon 

 Press, Oxford, 1908.) 21s. net. 



This large book (IB inches by 10 inches) contains an enlarged coloured 

 drawing of a section of each flower, as well as numerous pen-and- 

 ink drawings of details. Each type is treated elaborately, carefully, 

 and accurately under the headings Distribution, History, Description, 

 Variation, Floral Diagram, Pollination, Monstrosities, &c. In fact 

 nothing seems to be omitted that the observer must look for. The only 

 danger might be that with such an exhaustive treatment before him 

 the student may be tempted to forego his own necessary examination 

 of living plants. Indeed the author says: "Although the text is based 



