674 



SCIENCE 



[N. S. Vol. XXIX. No. 747 



While it is true that Persoon, and nearly 

 all the students of fungi in this period, studied 

 only external characters, it is equally true that 

 Persoon and Fries and the majority of the 

 workers of their time preserved a considerable 

 numher of their fungi, and their collections 

 are now available for study. The result is 

 that a majority of the names from Persoon 

 down can be fixed with a degree of definite- 

 ness which is impossible for those described 

 before his time. Objection may be raised that 

 many of Persoon's types are missing from his 

 herbarium; that herbarium specimens are 

 liable to become interchanged, and that in 

 other cases it is often difficult or impossible to 

 determine just what his type of a particular 

 species was. There is undoubtedly force in 

 this argiunent, but it must be admitted that 

 specimens, although sometimes confused, are 

 the most reliable bases for determination that 

 we have, and the same objections may be 

 brought against any other collection, even 

 against some of those of quite recent date. 



Some mycologists, perhaps, might be will- 

 ing to begin their nomenclature with Persoon, 

 but would urge that his more mature and 

 elaborate work, the " Mycologia Europsea," 

 should be chosen as the starting-point. To 

 the mind of the writer the principal objections 

 to starting with this later work are: (1) 

 That its publication extended over several 

 years, from 1822 to 1828; (2) that it was al- 

 most exactly contemporaneous with another 

 equally, if not more important work, the 

 " Systema Mycologicum " of Fries ; (3) it, 

 therefore, does not stand out in a class by 

 itself at the beginning of an epoch. 



It has been suggested by certain students 

 of fungi that the " Systema Mycologicum " of 

 Fries should be used as the starting-point for 

 mycological nomenclatura While the writer 

 recognizes fully that this work is one of the 

 most important and influential systematic 

 mycological contributions yet produced, and 

 that scientifically it was a great advance upon 

 the " Synopsis Methodica Fungorum " of Per- 

 soon, yet he believes that no lack of apprecia- 

 tion of its value is shown in the conviction 

 that it is not so natural a starting-point for 



nomenclature as is Persoon's work. The fol- 

 lowing reasons may be given in support of 

 this opinion: (1) The publication of the 

 " Systema " extended over several years from 

 1821 to 1832, a long period of time which 

 would, in fact, establish difierent starting- 

 points for the various groups of fungi. (2) 

 In the year of publication of each of the 

 earlier parts appeared important works by 

 other authors (e. g., S. F. Gray, 1821 ; Persoon, 

 1822; Schweinitz, 1822; Greville, 1823), in 

 which cases it would be difficult if not impos- 

 sible to determine priority of publication. (3) 

 It, therefore, does not stand out in a class by 

 itself at the beginning of an epoch, but is one 

 of a number of publications on the same sub- 

 ject which appeared about the same time. (4) 

 While Fries's system of classification was 

 much more elaborate than that of Persoon, 

 and showed a better understanding of rela- 

 tionships and of the relative value of char- 

 acters, it was in many, if not most, of the 

 groups founded directly upon that in Per- 

 soon's " Synopsis." ° (5) Fries's species are 

 no more capable of positive identification at 

 the present time than are those of Persoon. 



The third period in the development of my- 

 cology began in the decade between 1860 and 

 1870, when the second and most important 

 change came over the aspect of the study of 

 fungi. This movement was inaugurated by 

 the publication of the Tulasnes' " Selecta 

 Fungorum Carpologia" (1861-1865) and of 

 de Barys " Morphologie und Physiologie der 

 Pilze, Flechten und Myxomyceten " (1866). 

 Most of the work done before this time had 

 consisted in the almost interminable species- 

 making on the basis of the external and gross 

 features of the plants examined, but from this 

 time on the attention of students was directed 

 to the study of the morphological details and 

 the development of fungi, a kind of investiga- 

 tion which has laid the foundation for sounder 

 systems of classification. In some respects it 

 would be better to start the nomenclature of 

 fungi with some important work in which the 



" For a concrete example see the present author's 

 analysis of the relation of Fries's classification of 

 the fleshy diseomyeetes to that of Persoon in Bull. 

 Torr. Bot. Club, 27: 464-466, 1900. 



