282 THE JOURNAL OF BOTANY 



while stress will be laid upon those whose development is of special 

 importance from the phylogenetic point of view. 



The present volume contains a general introduction and the 

 first instalment of the special portion, comprising an accomit of the 

 Thallophytes. Volume ii., containing the Cormophytes, is promised 

 for next year. The general introduction, which occupies forty-four 

 pages, contains a short history of the evolution of systematic botany, 

 and a sketch of the value of homology, embryology, geographical 

 distribution, and other factors in determining phylogenetic relation- 

 ships. 



At the commencement of the special part Professor Wettstein 

 gives an outline of the classification which he adopts. The plant 

 world, he says — as far as our present knowledge goes — includes 

 organisms belonging to seven great developmental series, or stocks, 

 as follows : — 



i. Myxophyta. iv. Euthallophyta. 



ii. Schizophyta. v. Phaeophyta. 



iii. Zygophyta. vi. Rhodophyta. 



vii. Cormophyta. 

 Stocks i.-vi. are considered in the present volume, and the majority 

 indicate by their name the character of the organisms included. 

 Myxophyta are the Myxomycetes, including also Plasmodiophora. 

 Schizophyta comprise the two divisions fission-algae and fission- 

 fungi, or the old CyanophycecE and the Bacteria, which are 

 generally thus associated in recent arrangements. Zygophyta 

 contains the PeridinecB (which, if plants, must be put somewhere), 

 the BaciUariea or Diatoms, and the ConjiiyatcB, the latter com- 

 prising the three families Desmidiacea, ZygnemacecB, and Meso- 

 carpacecB. Euthallophyta include two classes — one the Cldorophycea, 

 or the rest of the green alg£e, and a second the Fungi. Phaeophyta 

 and Rhodophyta are the brown and red algae as generally under- 

 stood. Thus the important departure from systems generally in 

 vogue is the bringing together of the green algas and the Fungi in one 

 group, and the exclusion at the same time of the two other large 

 groups of sea-weeds. If, however, we accept the view of the 

 evolution of the Fungi as a whole from a common algal stock, 

 there is no doubt that the most nearly allied algae are to be found 

 among the C/dorophycea, and Prof. Wettstein is therefore phylo- 

 genetically justified in his - distribution of the groups. But as a 

 matter of convenience we much prefer the more usual method, 

 such as, for instance, is adopted in Prof. Engler's Fflanzenfamilien 

 — namely, the consideration of the great groups of Algae as one 

 section, and the great group of Fungi as another section of the 

 subkingdom Thallophyta. Even if we grant that the Fungi have 

 sprung from a common algal stock, which presumably finds its 

 nearest representative in the CIdurophycecB, we must bear in mind the 

 great development along widely diverging lines that has occurred 

 since the origin of the group, which development removes it as a 

 group far more widely from the Alg^, considered as a whole, than 

 the generally received subdivisions of Algae are removed from each 

 other. 



