Although it was originally intended that the second part of the Host 

 Index should include everything after Polypetalae, it has seemed best to 

 issue a second part including only Gantiopetalae and Apetalae as those 

 divisions cover an unexpectedly large number of pages. The re- 

 mainder of the work will appear in November and the authors request 

 that botanists having errors or omissions to report in the parts already 

 issued would kindly inform them regarding such errors and omissions 

 at an early date in order that the corrections and additions may be in- 

 serted in the forthcoming third part. It should be borne in mind that 

 unpiiblished hosts are not included in the present Index. Also that 

 in the case of some very common fungi occurring on many different 

 hosts it has not been found practicable to include all known hosts unless 

 the species are of economical interest. Since most Myxomycetes can 

 hardly be said to be parasitic on particular species of Phaenogams, in 

 the present part, the Myxomycetes have, as a rule, been omitted except 

 where their rarity or some special peculiarity warranted referring to 

 them in connection with certain hosts. 



W. G. FARLOW. 



Cambridge., Mass. 



