Studies of western tree rusts. VII. Inoculation experiments with pine stem rusts (CronartiumandEndocronartium)

摘要

Results from 35 cross-inoculation experiments provide confirmatory and new information on the life histories and taxonomy ofCronartium coleosporioidesArth.,C. coleosporioidesf.albumf. nov.,C. comptoniaeArth.,Endocronartium harknessii(J. P. Moore) Y. Hirats., and thePeridermium filamentosumcomplex. Stalactiform rust (Peridermium stalactiformeArth. amp; Kern) is accepted to be the aecial state ofCronartium coleosporioides; there is no evidence of its direct spread from pine to pine. A white-spored form ofC. coleosporioidesis named and described from specimens obtained by inoculation. Gall rust of western Canada appears to belong to the autoeciousEndocronartium harknessii; there is no evidence that heteroecious forms of it occur in western Canada. The existence of heteroecious and autoecious forms of limb rust (Peridermium filamentosumcomplex) is confirmed by inoculation results and germ-tube morphology. No morphological difference in the uredinial or telial states could be found between heteroecious limb rust andCronartium coleosporioides.