viu PREFACE 



and T. J. Burrill, Bacteria; G. M. Reed, Perisporiales; G. P. Clin- 

 ton, Ustilaginales; J. L. Sheldon, Ascomycetes in part; D. Red- 

 dick, Ascomycetes in part; J. C. Arthur, Uredinales; F. D. Heald, 

 Fungi Imperfecti in part; F. C. Stewart, Fungi Imperfecti in part; 

 H. Metcalf, Basidiomycetes in part; to Mrs. Flora W. Patter- 

 son for aid in securing descriptions otherwise unobtainable; to 

 Dr. Marshall Avery Howe for assistance with the glossary; to 

 Messrs. Norton, Rosenkranz and Fawcett, for aid in proof- 

 reading and in preparation of the manuscript, though no re- 

 sponsibility for error attaches to those who have so kindly 

 aided. 



It is probable, owing to the present unsatisfactory condition of 

 taxonomy of the fungi, loose and imperfect description of species, 

 disregard of generic limitation, lack of knowledge regarding the 

 limits of specific variation, influence of environment, biologic host 

 relations, etc., that many of the species treated in the text are 

 untenable. The author has, however, attempted so far as possible 

 to reflect the facts as they appear in the light of present knowledge 

 and has deenied it more useful to err on the side of conservatism 

 than to attempt to reduce the apparent number of species by con- 

 solidation without full and complete evidence as to the real identity 

 of the species in question. ' 



F. L. Stevens. 



Mayagtjez, Porto Rico. 



