Meria laricis, a needle cast pathogen of Larix spp. in North America and Europe, has no known ascigerous state, possibly having permanently lost the ability to reproduce sexually and thus representing an obligately asexual mitosporic holomorph. Comparisons of nucleotide sequences from the internal transcribed spacer region of M. laricis, Rhabdocline spp., and several genera of inoperculate discomycetes show that isolates of M. laricis form a monophyletic clade within the ascomycete genus Rhabdocline. Cladistic analysis of infraspecific taxa of Rhabdocline and ordinal placement of the genus are discussed. Results of cladistic analysis suggest that possession of an amyloid ascus pore is an unreliable character for differentiation of species and subspecies.
