SummaryThe connection betweenCeralostomellaandGraphiumshown in cultures in which both appear suggests the possibility thatGraphiummay be in a state of evolution; perhaps at one time it regularly formed the imperfect stage ofCeratostornella.In the United States the cases in which this connection can be demonstrated seem to be few; in Europe they are more frequent.The fungus that produces bothCeratostomellaandGraphiumis regarded by the writer as a strain ofCeratostomella pilifera(Fries) Winter, which is one of the commonest blue-staining fungi in lumber yards. Although there are many strains of this species that vary in minor details, such as the size and the shape of their perithecia and their habits of growth on and in the sapwood of hardwoods and of softwoods, the strains are not so different that they should be classified as distinct species. A careful study of the fungi grown under cultivation has convinced the writer that there is no line that can be drawn between one strain and another.