133 



not. According to Magnus this lack of singleness invalidates the name for re- 

 placing that of the De Candollean genus Gymnosporangiuvi. It does not do so, 

 however, in the writer's opinion, but it makes it necessary to decide which of the 

 two species included is to be accepted as the type of the genua. 



The idea of definite and unchangeable types is of comparatively recent 

 growth. The type of a species is the individual plant to which the name is first 

 given, and the type specimen is therefore an important adjunct in fixing the name 

 and character of the species. In like manner the type of a genus should be the 

 species mentioned under it, if there is but one given, but if more than one be 

 given, and the author has neglected to designate the one to be accepted, it would 

 seem to require for the sake of uniformity and stability that the first species 

 named under the genus be assumed to be the type. This method in whole or in 

 part has been ably advocated by Underwood, Cook, Jordan, Coville, Ward, 

 Greene and others. Up to the present time it has been put into rigid practice to 

 a limited extent only, the revision of American ferns by Prof. Underwood being 

 the most conspicuous example, but it seems to the writer that the general ac- 

 ceptance of the rule will go far toward furnishing a stable basis for taxonomic 

 nomenclature. To one who has watched the course of the present movement for 

 a nomenclature that stands squarely upon priority, guided by uniform procedure 

 rather than by individual judgment, the rule of types here set forth must seem a 

 necessity that will inevitably be adopted sooner or later. It is for the sake of 

 lending a hand in bringing about so desirable an end that the study of the cedar 

 apple nomenclature is here presented. 



If the rule of taking the first species mentioned under a genus as its type is 

 applied, there can be no question that Adanson's genus Puccinia is to be accepted 

 as a name antedating Gynmosporangiiim, and we may waive the discussion of the 

 exact determination of the type, brought forward by Magnus. But this does not 

 settle the matter. 



In Linnaeus' Species Plantarum of 1753, which is accepted as the beginning of 

 valid nomenclature, only two species occur belonging to the Uredinfce ; one is 

 Lycoperdon epiphyllum, now called Puccinia epiphylla (L. ) Wettst., and the other is 

 Tremella juniperina, known to be unquestionably Gymnosporangium juniperinum 

 (L. ) Wint. Linnaeus' genus Tremella contains seven species, the one just men- 

 tioned being the first, while the six which follow do not belong to the Uredinew. 

 The first species is characterized as follows (p. 1157) : 



" Tremella sessilis membranacea auriformis fulva. Fl. miec. 1017. 

 Byssus gelatinosa fugax, junipero innascens. /7. lai>p.5'il. 

 Habitat in Juniperetis primo vere." 



