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COMPARATIVE STUDY OF THE DEVELOPMENT OF 
———FRICHURUS SPIRALIS AND STYSANUS' STEM-. 
ONITES. 
: H. HASSELBRING. 
(WITH PLATES XXIII AND XXIV) 
TRICHURUS SPIRALIS. 
DurinG the autumn of 1898 a hyphomycete, closely resem- 
bling the members of the genus Stysanus, was found on decaying 
wood brought into the laboratory of Cornell University. The 
principal difference between this fungus and the species of 
Stysanus lies in the fact that the capitulum of the former is 
densely beset with long, tortuous, sterile threads, recalling at 
first sight the spiral setae surrounding the perithecia of some 
species of Chaetomium. This character shows the plant to be 
closely related to Zrichurus cylindricus Clements & Shear." In 
the following pages I will refer to it as Zvichurus spiralis, leaving 
a discussion of its history and nomenclature until the end of this 
paper. The plant was obtained in pure culture, and grown on 
agar and on bean stems, in order to study the development of the 
sporophore, and to determine, if possible, whether any other 
forms of fructification existed in the life cycle of the fungus. 
The perfect sporophores of Trichurus spiralis, growing on 
agar or on bean stems, appear as small fluffy heads, which are 
either linear or elongated oblong, and obtuse or pointed at the 
summit. In agar they appear in small clusters of several heads 
near the center of the colony, but when grown on bean stems 
they arise over the entire surface of the substratum. Usually 
the sporophores are simple, but not infrequently they are 
branched near the base, and bear several smaller heads, or the 
head itself may be divided above. These rather abnormal fortis 
are probably caused by an abundance of nutriment. While 
* Rept. Bot. Surv. Nebraska 4:7. 1896. 
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