Apeil 23, 1909] 



SCIENCE 



671 



very numerous among the Ascomycetes, and 

 will at once occur to any one at all familiar 

 with the fungi. A few concrete examples will 

 perhaps put the matter in a more definite 

 light. The genera and species of the Phyco- 

 mycetes are based almost entirely on micro- 

 scopic characters. Among the powdery mil- 

 dews the genera Sphwrotheca and Erysiphe, 

 as well as Podosphcera and Microsphosra, can 

 not be distinguished from each other without 

 the use of the microscope. Most of the genera 

 and species of the Pyrenomycetes are founded 

 on characters drawn from the asci and spores, 

 which can not be made out with the unaided 

 eye. Among the Discomycetes the genua 

 Trichoglossum is represented in America by 

 about half a dozen species which are indis- 

 tinguishable by their gross features. The 

 genera Geoglossum and Corynetes can not be 

 told apart by external characters. The same 

 is true of Barlma and Eumariaj Sphcerospora 

 and Lachnea, and many others. In nearly all 

 of these genera are whole gToups of well 

 marked species which are based entirely on 

 minute microscopic characters. Specific lim- 

 its among the rusts, smuts and other groups 

 are too familiar to need mention. On the other 

 hand, it is equally true that there are certain 

 fungi which are so unique and well marked 

 that they stand off by themselves, and can be 

 much more certainly recognized by external 

 features alone. Such species occur more com- 

 monly among the larger fleshy and woody 

 forms, but even here minute hymenial char- 

 acters are recognized as being of the greatest 

 systematic importance. No one can venture 

 to assert that carefiil students of these better 

 marked forms may not soon discover micro- 

 scopic features at present unused which may 

 entirely upset our ideas of their specific limits. 

 It is not necessary to dwell further on this 

 phase of the subject, for the facts are too 

 familiar to need elaboration. Enough has 

 been pointed out to emphasize the fact that 

 the number of species' of fungi which may 

 be placed with certainty on the basis of ex- 

 ternal characters alone is comparatively smalL 

 If, therefore, the accurate determination of 

 most of the species of fungi on the basis of 

 gross characters alone is next to impossible 



when the living plant is actually before one, 

 how much more uncertain must be the identi- 

 fication of the species of older writers, which 

 are represented by only brief descriptions of 

 the most obvious external features, or at best 

 by figures often crudely drawn or inaccurately 

 colored. The simple fact is that the raajority 

 of the species of fungi described by writers 

 before 1800 can not be recognized with cer- 

 tainty at the present time, when measured 

 according to present-day standard. Yet sys- 

 tematic literature is filled with the references 

 of well known fungi to names dating from 

 Linnasus, Scopoli, Jacquin, Batsch, Bulliard, 

 Paulet, Schaefier, Adanson, Schrader and 

 many others, the majority of which are at best 

 involved in doubt. Of course it is perfectly 

 possible for one to si)eculate on the probabil- 

 ities in such cases, but positive conclusions 

 can never be inferred from doubtful premises, 

 and he will be no nearer definite knowledge 

 at the end of his speculations. The writer 

 firmly believes that in the field of systematic 

 mycology a single gram of knowledge is of 

 more value than kilos of guess-work, suppo- 

 sition and uncertainty, and he wishes here to 

 raise the question and to invite discussion as 

 to whether the time has not come to take steps 

 to eliminate from consideration these old 

 names, the great majority of which can never 

 be definitely fitxed. 



We are thus led naturally to inquire Why 

 should myeological nomenclature date from 

 Linnssus's " Species Plantarum " of 1753, and 

 thus include this mass of undeterminable 

 names? While Linnsus had a good under- 

 standing of vascular plants the distinguishing 

 characters of which are gross and external, 

 his knowledge of the lower organisms, especi- 

 ally of algae and fungi, was very slight. In- 

 deed, it seems probable that very little that he 

 wrote concerning the fungi was based on his 

 own first-hand knowledge, but that his work 

 with these plants consisted principally in the 

 application of binomial designations and brief 

 descriptions to those figured by his predeces- 

 sors. The distinguished botanists of Harvard 

 University have stated the matter so admir- 

 ably that I can do no better than to quote 

 from them as follows : 



