234 



Mycologia 



Americans and are less disposed to make convenience a promi- 

 nent argument. However, it appears from another proportion 

 that Europeans are more disposed to retain lichens as a distinct 

 natural group than are Americans ; and since this is true, there is 

 for them not so much conflict between theoretical and practical 

 considerations, so that one would not expect so much prominence 

 in their replies to the matter of convenience in classification, even 

 though they might be as strongly in favor of it as Americans. 

 The last proportion tends to show that Europeans more commonly 

 favor the dual-nature theory, or, an outright consortium-theory 

 than do Americans. Three (3) Americans and 5 Europeans ex- 

 pressly state that they regard present knowledge insufficient to 

 warrant distribution. On the whole, the proportions and figures 

 seem sufficient to demonstrate that Europeans are less disposed to 

 break with established usage regarding the systematic disposition 

 of lichens than are Americans. This is what might be expected 

 when it is recalled that nearly all the traditions regarding lichens 

 have had their birth in Europe. There is just one notion regard- 

 ing lichens that has been explicitly expressed in America only and 

 that is that they should be distributed to the exclusion of the class 

 Lichenes. Careful inquiry and thorough examination of the 

 literature has not brought to light a single instance of such dis- 

 tribution by a European, while three or more Americans have 

 distributed lichens in papers or books. 



It would be impossible to state many of the views expressed in 

 the correspondence except in the tabular presentations given 

 below. 



By inference or direct statement, 15 clearly defined reasons for 

 maintaining lichens as a distinct group of plants are contained 

 in the replies (see first table) while only two reasons are assigned 

 for distributing them (see second table). Those who replied are 

 grouped as well as could be done according to their fields of 

 botanical work. Twenty (20) . replies came from botanists who 

 are known for work not falling in fields contained in the same 

 vertical column in the tables. The views of these persons are 

 given in each of two vertical columns, while those of the remain- 

 ing 95 botanists are expressed only once in the tables. , The 

 figures (i6-i a ) under lichenists in the first vertical column of the 



