PLANT SUCCESSION 93 



be calculated to enhance our previous sufficiently good Opinion of 

 Professor Clements as an ecologist ; but it proclaims him in the first 

 rank as a writer of text-books. For this is more than the " general 

 part of a monogi-aph " ; it is a text-book of Ecology, treated as all 

 biological text-books should be, but too seldom are, treated, from the 

 historic standpoint and from the aspect of general evolution. 



The work opens with the conception of the unit or climax for- 

 mation as an organic entity, and, like all organisms, ever changing, 

 never fixed; and the principle that every formation has its phylo- 

 geny as well as its ontogeny is kept throughout in constant v'iew. 

 A striking feature of the book is its wide range, not only of sub- 

 ject, but also of concrete example. This is a natural result of the 

 historic treatment ; so the author is preserved, in spite of his 

 nationality and the scene of his strenuous practical labours in the field, 

 from laying undue stress upon his native continent ; no more space is 

 accorded to the vegetation of North America than is demanded by its 

 vast size and importance. This remark, however, unfortunately, does 

 not apply to the illustrations ; for the large majoritv of these are of 

 vegetation-groups in the United States. These, ho\vever, have the 

 advantage, presumably, of the author's personal and able choice, many 

 of them being reproduced from original photographs. Besides 51 

 figures in the text, many of them diagrams, maps, and phylogenetic 

 schemes, there are 61 plates. Of these, 59 are full-page reproductions 

 from photographs, each page containing two pictures (three in one or 

 two cases), about 4|"x4" or 4i"x3|". They are excellent beyond 

 all praise, especially considering the 'small space available, and are 

 admirably chosen to illustrate general principles — a small photograph 

 cannot be hoped to do more. Seven of the pictures are taken from 

 British scenes ; one from Denmark ; the remainder, one hundred and 

 eighteen in all, are from North and Central America. In consulting 

 these, the British student will labour, in most cases, under the disad- 

 vantage of being unfamiliar with many of the plants in question, 

 even the dominant ones. He may even "be driven to a herbarium ! 



The work is arranged in fifteen chapters, and a glance through 

 the titles of these will suffice to exhibit the thoroughness with which 

 the author has treated his subject— a thoroughness which has not led, 

 as it does m many cases, to prolixity and obscureness. The book is 

 written in a refreshing style, and i^^s, from the point of view of the 

 earnest student, almost dangerously readable. The whole is divided 

 clearly into titled paragraphs, and their titles appear, under their 

 respective chapters,^ in the table of contents at the beginning, which is 

 thus a sort of j^recis of the whole — an admirable arrangement, not 

 common enough, even in the most modern books. An introductory 

 chapter defining basal principles and fundamental terms deals with the 

 " Concept and Causes of Succession." Some of our European students 

 may be alarmed to hear a unit succession called a sere ; and, having 

 recovered from this alarm, he will be menaced further with cosere, 

 prisere, Jii/drosere, suhsere, not to mention eosere, ceneosere, r/eosere, 

 . palaeosere, etc. Professor Clements claims for the word that it is 

 "significant, short, euphonic (sic), and easy of combination"; and 

 has the further advantage of both Greek and Latin parentage— an 



