Chaetosphaeria albida, C. bombycina, and C. metallicans are described and compared with other Chaetosphaeria taxa using morphological and molecular methods. The fresh ascomata of C. albida are almost white, translucent, and aereolate; they are papillate with a distinctive 4-layered peridium, and the ascospores are scolecosporous, multiseptate, and hyaline. C. bombycina is similar, but the fresh ascomata are light fawn-grey with a reflective silken appearance, non-papillate, and the similar peridium is 3-layered. C. metallicans has ascomata which are blue-black, shiny and metallic when fresh; the thick peridium is heavily melanised, and the ascospores are straight to allantoid, 3-septate, and hyaline. The scolecosporous ascospores of C. albida and C. bombycina would have traditionally referred these taxa to Lasiosphaeria. However, like C. metallicans, they lack a peridial tomentum, and have asci with light-refractive, non-amyloid apical rings, without a sub-apical globule. Despite the major differences in spore shape and ascomal wall structure, analyses of the LSU and ITS regions of ribosomal DNA suggest that genetically all three fall within Chaetosphaeria, near to C. raciborskii, and in a sister clade to the type species C. innumera. The placement of these species considerably expands current morphological conceptions of Chaetosphaeria, particularly in terms of ascomal wall appearance and structure, and confirms the existence of a scolecosporous group within the genus. in the search for morphological characters which mimic genetic relationships, this study further elucidates the relationship between the Chaetosphaeriaceae and the Lasiosphaeriaceae.
- New Zealand
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Plant Science