X PREFACE 



In reference to the omnipresent vexed question of nomen- 

 clature, a word is perhaps necessary. De Candolle's rule, 

 " the first authentic specific name published under the genus in 

 which the species now stands," may be true philosophy, but it 

 is certainly an open question how that rule shall be applied. 

 If an author recognized and defined a given species in times 

 past, and, in accordance with views then held, assigned the 

 species to a particular genus, common honesty, it would seem, 

 would require that his work be recognized. To assume that 

 any late writer who may choose to set to familiar genera limits 

 unknown before shall thereby be empowered to write all species 

 so displaced his own, as if, forsooth, now for the first time in 

 the history of science published or described, is not only abso- 

 lutely and inexcusably misleading, but actually increases by 

 just so much the amount of debris with which the taxonomy of 

 the subject is already cumbered. 



In face of a work so painstaking and voluminous as that of 

 Rostafinski, and in view of the almost universal confusion that 

 preceded him, it would seem idle to change for reasons purely 

 technical the nomenclature which the Polish author has estab- 

 lished. Especially is this true in the case of organisms so very 

 perishable and fragile as those now in question, where com- 

 parative revision is apt to result in uncertainty. We had pre- 

 ferred to leave the Rostafinskian, i.e. the heretofore current, 

 nomenclature untouched ; but since other writers have pre- 

 ferred to do otherwise, we are compelled to recognize the 

 resultant confusion. 



Slime-moulds have long attracted the attention of the student 

 of nature. For nearly two hundred years they find place more 

 or less definite in botanical literature. Micheli, 1729, figures a 

 number of them, some so accurately that the identity of the 

 species is hardly to be questioned. Other early writers are 

 Buxbaum and Dillenius. But the great names before Rosta- 

 finski are Schrader, Persoon, and Fries. Schrader's judgment 

 was especially clear. In his Nova Genera, 1797, he recognizes 

 plainly the difference between Slime-moulds and everything else 



