Taxonomy of the genus Ceratocystis in Manitoba

Abstract

From Manitoba hardwoods and conifers, 183 collections were examined for Ceratocystis species. Most previously described species, including many type specimens, were also examined.Among the morphological characters used to separate species of Ceratocystis, those of the ascospores are the most reliable and were given major stress herein. The nature of the conidial state, which is distinctive in some species and of diagnostic value in others, was also considered in preparing species diagnosis, and the method of conidium formation was therefore also stressed.The genus Ceratocystis is organized into four groups based mainly on ascospore characters: (1) the Minuta group; (2) the Ips group; (3) the Fimbriata group; and (4) the Pilifera group. It is felt that such groupings reflect the affinities between various species. A key to the groups of species and keys to the species of each of the four respective groups are provided. The keys include 70 species, 50 of which are found in Manitoba.