MoNoGRAPH OF CHAETOMIUM AND ASCOTRICHA 157 
these reasons that specimens are so often broken and damaged. 
In many cases, therefore, it is unfortunate that new species names 
have been freely applied to such forms as have seemed to differ 
from those already named, before it was determined with cer- 
tainty that such differences as existed were characteristic of the 
living plant and not peculiar to the dry specimen. Moreover, 
since all species of Chaetomium which have come to the attention 
of the writer lend themselves to easy culture on various media, 
it would seem highly desirable that they should be carefully 
studied in all stages of development in order that their true 
characteristics may be determined. 
As a result of a thorough review of the literature one hundred 
and fourteen species names and fourteen variety names have 
been found which have been applied to forms supposedly Chae- 
tomia. In the present revision a considerable number of changes 
have been made. Names which were first used in connection 
with good species have been retained, while many others have 
been listed as synonyms thereto. For reasons given elsewhere, a 
considerable number have been excluded, and the writer feels*that 
the use of such names should be discontinued. Certain new 
names representing new forms heretofore unrecognized have been 
added to the list of known species. Nevertheless according to 
the best judgment of the writer, the genus should include not 
more than twenty-eight species. 
А careful study of the genus Bommerella has led to its in- 
clusion under Chaetomium, while on the other hand Ch. chartarum 
(Berk.) Winter and Ch. pusillum E. & E., which possess similar 
characteristics, yet are markedly different from those of the typical 
species of Chaetomium, have been included in a separate genus 
to which the name A scotricha, first given by Berkeley to the plants 
which Winter later renamed Ch. chartarum, has been apphed. 
In connection with his work the writer has been especially 
fortunate in being able to examine exsiccati in several herbaria 
and to study a large number of type specimens which have been 
generously contributed by many individuals both in this country 
and abroad. Sets of specimens as complete as possible and 
containing as many of the writer's forms as are available have 
been distributed to the Royal Botanic Gardens at Kew, the 
