Classification of Ohio Ascomycetes 
17 
of the relationships among ascomycetes. Especially will knowledge of 
nuclear behavior in the reproductive tracts finally have considerable 
weight in the arrangement of ascomycetes, since it will enable us to 
decide just what portion of an archicarp is the ascogonium. At present 
nuclear behavior is not known in the sexual reproductive tracts of any 
lichens save one (Bachman 2), nor is it well understood in many other 
ascomycetes. According to Claussen (16), delayed nuclear fusions and 
homologous alternation in ascomycetes strongly resemble the conditions 
found in certain basidiomycetes. This points to the origin of the latter 
group from the former, and further studies of nuclear behavior in both 
groups may shed some light on the relative rank of the various ascomy¬ 
cetes. The rather uniform character of ascogenous hyphae and the 
peculiar origin of asci from them, together with the characteristic be¬ 
havior of the nuclei within these structures, is probably the strongest 
proof of the common, or at least similar, ancestry of all ascomycetes. 
There is another theory of the origin of ascomycetes that must be 
noted. Bucholtz (15) has presented a modification of the theory of 
origin of the Ascomycetae from the Phycomycetae which is especially 
worthy of consideration. He considers Endogone to be a plant whose 
fruit results from the conjugation of heterogametes. After cytoplasmic 
fusion, the two nuclei pass together from the oogonium into a protrusion, 
which might be regarded as a primitive ascus. Here the nuclei fuse. 
Not far removed from this is the formation of asci as direct outgrowths 
from the single fertilized ascogenic cell described by Faull (26) for 
Amoj'phomyces and said to occur in some other genera of the Laboul- 
beniales. Nienburg (51), Claussen (16), and others have also' presented 
strong arguments for this theory, which would make trichogynes and 
ascogenous hyphae structures which arose independently in ascomycetes, 
would deny the origin of the Ascomycetae from the Rhodophyceae, and 
would account for the resemblances between these two groups by 
parallelism alone. However, the evidences of relationship between the 
two groups are too strong to be ofifset by such facts as have been ad¬ 
vanced hitherto for the origin of the Ascomycetae from the 
Phycomycetae. 
It will be seen from the above presentation that no attempt has been 
made to consider the problem of classification of ascomycetes merely as 
it applies to our studies in Ohio. The outline of classification that is 
presented herewith is the result of a study of the problem concerned 
with the phytogeny of all ascomycetes. To base any system of treatment, 
even for a small area, on anything less than a consideration of all 
