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The Genus Rosellinia in Indiana. 



Glen B. Ramsey. 



In this paper it is the author's purpose to present the genus Rosellinia 

 as found in Indiana. Limited means for collecting and the unfavorable 

 weather conditions during the past year for the growth of this class of 

 fungi render an exhaustive treatise on the genus Rosellinia impossible. 

 Only those species that have been found in Indiana, together with their 

 descriptions and an account of their habits and habitat have been in- 

 cluded. A description of some of the more common parasitic species has 

 also been appended. 



There are now over one hundred seventy species described, the most of 

 them being saprophytic. As in other genera of the Pyrenomycetes, Rosel- 

 linia has a vegetative phase which is found in the substratum or host. The 

 white thread-like mycelium may readily be found in decaying logs and 

 stumps. There are, however, some species that seem to flourish in wood 

 that is quite firm. In most cases the actively parasitic stage is found on 

 the roots and consists of a great abundance of white mycelium which does 

 the greatest harm to the plant. This mycelium growing into the root sys- 

 tem stops up the xylem cells, prevents the roots and rootlets from perform- 

 ing their functions, thus finally starving the plant to death. 



The fruiting parts of Rosellinia do not develop until late in the season, 

 the conidial stage being found in late summer or early autumn, with the 

 perfect or ascigerous stage following and maturing in late fall or early 

 winter. The perithecia with their abundant asci and filiform paraphyses 

 are found in good condition for collecting from October to February. The 

 spring rains and warm weather, together with the frost action during the 

 winter, cause the perithecia to disintegrate rapidly when spring comes. 

 Most of the specimens at band were collected during the early winter 

 months. 



In Rosellinia the perithecia are more or less crowded or gregarious 

 and superficial, but often having the base sunken in the matrix. 

 Perithecia ovate to sub-globose, papilliate, sub-carbonaceous, black, bare 



