160 MONOGRAPH OF CHAETOMIUM AND ASCOTRICHA 
With the publication of his Icones by Corda (21, 22, 23) in 1837, 
1838 and 1840 came quite a new era in the history of the genus. 
This author amended the original description given by Kunze as 
follows: ‘‘Peridium membranaceous, at length opening at the 
apex by a pore, clothed on the outside with opaque hairs, sup- 
ported by a more or less well-developed, fibrous hypothallus: 
spores grouped together, ascomorphic, pedicellate, at length 
discharged as simple powdery spores. Pedicels without mucous.” 
It may be readily seen that from the amended description one is 
able to form a much more accurate judgment of the characteristics 
of the genus. 
Corda was the first to study the internal structure which other 
authors had been content to call a gelatinous mass. He observed 
this to be made up of bodies which he called asci, though according 
to his description he was misled in believing that these bodies 
functioned as pedicels on which the spores were borne. Corda’s 
descriptions are for the most part illustrated by figures which 
are elaborate for his time, and while it is not possible to deter- 
mine with certainty all of the forms with which he dealt, several 
may be easily recognized. Of the seven new species described 
Ch. indicum and Ch. murorum stand out as those to be retained, 
while the remaining five have been referred to other genera, 
treated as synonyms, or excluded. 
Between the time of Corda and the appearance of Zopf's 
monograph in 1881 descriptions of at least thirty-two new species 
appeared. In fact so many contributions were made that it will 
be possible to mention here only those which furthered the ac- 
curate knowledge of the genus. In 1849 Fries (39) called attention 
to the fact that in Chaetomium the spores are formed in typica 
asci, though the asci are rarely conspicuous. This is the first 
recognition of the true character of the perithecial contents which 
Corda had mistaken for spore-bearing pedicels and which all- 
other writers had described as a gelatinous mass including spores 
Fuckel (42) and Cook (16) also made valuable contributions in 
1869 and 1873, respectively, in their descriptions of two new species 
under the names Ch. crispatum and Ch. funicolum. 
The well-known monograph of Zopf (113), to which reference ` — 
has been made on a preceding page, marked the appearance of а 
