Morphology, life cycle and taxonomy of rust fungi

Abstract

　Examinations of spermogonia of many genera and species of rust fungi revealed that morphological types can clearly be divided into 12, and if the positions of spremogonia in the hosts are disregarded, 6 groups. Morphological types of spermogonia strongly indicate phylogenetic relationships among rust fungi. Considering the spermogonial types as important taxonomic criteria, 14 families (later reduced to 13) have been recognized including two new families (Micronegeriaceae and Chaconiaceae). Two pine-to-pine stem rusts, one in the North America and another in Europe, have been proven by repeated inoculation experiments and cytological observations, to have endocyclic life cycles. A new genus Endocromartium has been established to accommodate the two species. Criteria of terminology of spore states of the rust fungi should be based on the positions in the life cycles and not according to their morphological types. Thirteen (13) anamorphic genera, including a new genus (Petersonia), have been redefined and recommended to be used in combination with ontogenically defined spore state names. Use of terms such as aecia Aecidium-type, uredinia Uredo-type, aecia Uredo-type, uredinia Aecidium-type, aecia Milesia-type and telia Peridermium-type are recommended.