BOOKS AND CURRENT LITERATURE 337 



culture medium of Chodat-Grintzesco might have been included with 

 profit. The recommended addition of potassium chromate or potas- 

 sium biGhrom.ate to the media has always been followed by disaster in 

 the reviewer's cultures. Perhaps under very special circumstances 

 such a procedure might be useful, but it certainly cannot be generally 

 advised. 



Space forbids the detailed discussion of the many interesting questions 

 of classification occurring to the reader. One such point may be men- 

 tioned. The order Protococcales is broadly defined. The author seems 

 quite justified in including here the Volvox series, though this disposition 

 is not accepted by Collins, Oltm.anns, or Pascher. The line between 

 major groups must be sharply drawn. Those species of Chlamydomonas 

 in which the habit is like Palmella and in which motile cells are only 

 rarely produced are plainly Protococcaceous. Chlamydomonas, therefore, 

 fits snugly in the Protococcales, and the other Volvocines must follow. 



Our old friend Pleurococcus vulgaris has become Protococcus viridis Ag. 

 Delimitation of the family of which this is the type is questionable. 

 Trochiscia and Chlorella, other genera in the Protococcaceae, show im.- 

 portant differences in reproduction from Protococcus. In fact, Proto- 

 coccus may just as well be considered a reduced member of the Ulotri- 

 chaceae, which its "protoderma state" nearly resembles. Trochiscia 

 and Chlorella fit equally well in the Autosporaceae. 



The reviewer agrees with the author as to the phylogenetic history 

 of the desmids. They are regarded as originally filamentous, then 

 unicellular, and last in some cases secondarily filamentous. 



The chapter on Occurrence and Distribution of Freshwater Algae 

 suffers from having much of the material proper to it distributed else- 

 where in the book. The chapter forms a good introduction to the 

 ecology of the group. The objection may be raised that the factors in- 

 fluencing the occurrence and distribution of algae are not sufficient^ 

 emphasized. The truth is we know next to nothing about these fac- 

 tors, and m.aterial is lacking for their discussion. 



The work as a whole is carefully done, and misprints and minor pec- 

 cadilloes are rare. Guillierm.ond will probably be annoyed by the 

 consistently odd spelling of his name, the pedan't will feel a twinge on 

 seeing "colonial unicells," the technician might object to the color reac- 

 tion of cellulose with chlor-zinc-iodine being given as "blue" — all these 

 in the first three pages — but the Ijotanist will welcome with pleasure 

 and profit this well arranged and comprehensive account of most of 

 the algal groups. True, much of it may be found in the British Fresh- 



THE PLANT WORLD, JVOL. 20, NO. 10 





