PREFACE TO FOURTH EDITION. 



npHE third edition of this Work having for some time been 

 out of print, and the demands of the public encouraging 

 the publisher to proceed with a new edition, I have entirely 

 revised the Appendix, adding descriptions of all the species 

 since discovered, so far as they relate to the Orders included in 

 this volume. The success which has attended the sale of this 

 Work, and the number of fresh observers it has brought into 

 the field, has greatly tended to the necessity for this revision. A 

 larger number of observers, over a still more extended area, will, 

 it is hoped, add further to our list by increasing the number 

 of known species. Hitherto one great cause of the paucity of 

 students of Fungi in this country, especially of the Microscopic 

 forms, has been the want of text-books on the subject, contain- 

 ing descriptions of the species, with figures illustrative of the 

 genera. Although this little volume only partly supplies that 

 want, by including the species found on living plants alone, it 

 has already proved of service ; this and its companion volume, 

 " Introduction to British Fungi," being (with one exception) the 

 only books on Fungi which have passed beyond a first edition 

 in this country ; a fact which appears to prove that they have 

 succeeded in furnishing a desideratum, and in giving an impetus 

 to the study. It is hoped that similar results will follow the 

 publication of this new edition. 



I\L C. COOKE. 



