40 THE PLANT WORLD 



these plant is given, beginning with Linnaeus, who inckided them in 

 his genus Mucor. The connection and relation between host and para- 

 site are discussed, and some interesting data regarding distribution 

 given. Some curious instances are given of species described as occur- 

 ring on plants upon which the fungus did not originate, its presence 

 being apparently accidental. The author thinks these instances may be 

 accounted for in some cases by the rubbing together of dried speci- 

 mens, or the repeated use of the same driers to which the perithecia 

 might adhere. It seems to us hardly probable that either of these sug- 

 gestions would account for the presence of the perithecia which have 

 been reported as occurring on Fomes fomentarins. It appears more 

 probable that the perithecia become accidentally detached from plants 

 growing in close proximit}'^ to the one on which they are reported. 

 However, the fact of such accidental occurrence should impress upon 

 collectors and authors the necessity of carefully guarding against such 

 errors. 



In his treatment of species, the author is very conservative. Sac- 

 cardo in his "Sylloge Fungorum " recognizes 111 species and 1 variety, 

 with 20 other " dubiae vel iuquirendae." In the present monograph, but 

 49 species and 11 varieties are recognized. Of these, 3 species and 2 

 varieties are described as new. This is in rather striking contrast to 

 the present tendency to multiply species. This broad conception of 

 species we are inclined to attribute in large pai-t to the close compara- 

 tive study of a great abundance of material from various parts of the 

 world. One can scarcely examine in an unprejudiced manner a large 

 series of specimens of any group of plants without recognizing their 

 great variability, and the indefiniteness of the dividing lines which ne- 

 cessitates a more or less arbitrary separation if any is to be made. A 

 careful study of types or authentic specimens of many of the species of 

 the older authors has cleared up numerous cases of doubtful identity 

 and synonomy, and quotations of original descriptions from publica- 

 tions which are inaccessible to many students, give opportunity for 

 judging the correctness of the author's interpretations. Citations of 

 literature, exsiccatae and synonyms are unusually complete. The work 

 is illustrated with nine plates, which add greatly to the value of the 

 book. More careful and exact citations of the types of species in the 

 cases in which such exist, would have increased the value of the work. 

 This omission is particularly noticeable in the case of the new species 

 described. The question of generic types is one which must also be 

 met in the near future, if any great degree of stability or uniformity in 

 nomenclature is to be secured. The work as a whole is most com- 

 mendable, and must remain for a long time the authority on this group 

 of fungi. — C. L. S. 



