370 



SCIENCE 



[N. S. Vol. XXX. No. 768 



many years of study, and Tufts College is 

 much to be congratulated on the way in which 

 it has availed itself of the privilege of publi- 

 cation. 



The work describes all the species of green 

 algae, exclusive of the desmids and stoneworts, 

 known to occur in North America from 

 Greenland to the West Indies and Mexico. 

 The characters of each genus (with the excep- 

 tion of four) are illustrated by figures of at 

 least one species. The figures, taken for the 

 most part from authoritative sources, are well 

 executed and will greatly assist the general 

 student to a clear understanding of generic 

 characters. An extensive bibliography is pre- 

 sented. The index is very full, including not 

 only the species and synonyms, but also struc- 

 tural and descriptive terms with references to 

 the pages in the text on which they are de- 

 fined, so that the index thus serves the purpose 

 of a glossary. 



The descriptions of species are clear and 

 concise and include a reference to the original 

 publication of the binomial, to some good 

 plate or figure, and when possible to some set 

 of exsieeatse, and conclude with records of 

 American localities to which are added the 

 distributions in other parts of the world. The 

 Phycotheca Boreali-Americana of Collins, 

 Holden and Setchell is naturally most fre- 

 quently cited among the exsieeatse as the one 

 most accessible for American students and 

 richest in American species. Mr. Collins as 

 chief editor of this set of algse has had excep- 

 tional opportunities to handle large quantities 

 of material and probably much of his work 

 bestowed on this exsiccata finds further and 

 fuller expression in this book. A considerable 

 number of American botanists will recognize 

 that through their contributions to the Phyco- 

 theca and in other ways they have had a small 

 share in making possible this account. 



The best test of the general value of such a 

 Work as this will be its usefulness in the hands 

 of those who are not algologists. This useful- 

 ness will depend very largely on the accuracy 

 and at the same time the simplicity of the 

 analytical keys. Good keys are necessarily 

 based on the more obvious characters which 

 are not always the most important systemat- 



ically, and perhaps nowhere in works of this 

 character can greater care be shown or is 

 greater judgment required than in the con- 

 struction of these more or less artificial 

 guides. Genera such as Bpirogyra with 38 

 species in this account, (Edogonium with 74 

 species and Cladophora with 53 species, illus- 

 trate the great difficulties. In some cases 

 Mr. Collins has been able to make use of keys 

 in certain monographs, as for example Hirn's 

 detailed account of the Qildogoniaceae, but for 

 the most part they are the result of his own 

 studies and ingenuity. His skill in this sort 

 of work has already been shown in the ad- 

 mirable accounts of the Ulvacese, Cladophoras, 

 etc., published at various timies in Rhodora. 

 The keys of this manual possess the character- 

 istics of clearness and simplicity shown in his 

 former work. Besides the keys to species 

 there are also keys to the genera, families and 

 orders, so that the synopsis is well planned in 

 respect to all the aids that enable the reader 

 to handle the text quickly and without eon- 

 fusion. 



A brief account of the general system of 

 classification is presented at the end of the 

 introduction, but so closely associated with 

 other matter that the attention of the reader 

 is not brought quickly to its notice as might 

 have been the case had the account been given 

 a separate heading, which its importance fully 

 justifies. Mr. Collins is not willing to follow 

 to the extreme those arrangements which 

 group the green algffi in large subdivisions or 

 classes according to the structure of the repro- 

 ductive elements and especially the ciliated 

 reproductive cells, and in this respect he takes 

 a conservative attitude. Only one group is 

 split off from the main assemblage of the 

 Chlorophycese — the Heterokontse, a small class 

 the forms of which are of uncertain relation- 

 ship. It seems even doubtful to the reviewer 

 whether this group (Heterokontas) is worthy 

 of such distinction, and there is much to be 

 said in favor of applying the name Chloro- 

 phyeese in its broadest signification with the 

 full understanding that it embraces a number 

 of distinct phyla. It is certainly hardly less 

 broad with such divergent groups as the Con- 

 jugales, Volvocales, Ulothrichales, Siphonales, 



