Microglossum

Abstract: Some genera of Geoglossaceae, characterized by colourless spores and positive iodine reaction of the ascus pore, are compared with respect to the structure of the stipe. Ochroglossum is reduced to the synonymy of Microglossum. Mitrula is regarded as a monotypic genus. The generic name Heyderia is restored. Thuemenidium is reintroduced to replace Corynetes. Nothomitra is proposed as a new genus to accomodate N. cinnamomea, a new species.

Abstract: Thuemenidium is a small earth tongue genus with three recognized white-spored species. Within Thuemenidium, T. atropurpureum and T. arenarium have been reported only from the northern hemisphere while T. berteroi is known solely in the southern hemisphere. We reviewed the ecology, examined the morphology and inferred the systematic positions of northern species of Thuemenidium from LSU-rDNA gene phylogeny of 48 taxa in Pezizomycotina including recent collections. Our results suggest that Thuemenidium in its current sense is polyphyletic and that T. atropurpureum, closely related to Microglossum and Leotia species, is a member of Leotiaceae (Helotiales, Leotiomycetes). Our phylogeny placed the other northern species, T. arenarium, in Geoglossaceae (Geoglossales, Geoglossomycetes), retaining genus Thuemenidium, pending further investigation.

Abstract: ognized as a family in the Inoperculates and therefore far removed from the Helvellaceae in the Operculates. In Nannfeldt's (1932) treatment of the Discomycetes it is placed in the Helotiales and is recognized as closely related to the Helotiaceae. As distinguished from the Helotia? ceae, the Geoglossaceae is usually separated by having clavate, capitate or pileate ascocarps with the hymenium covering the convex upper por? tion and the Helotiaceae having discoid, saucer-shaped or cupulate ascocarps (Durand 1908, Nannfeldt 1932, Martin 1940, Seaver 1951). In this study, Durand has been followed, with some modifications in the division of the Geoglossaceae into two tribes, the Geoglosseae and the Cudonieae. The Geoglosseae, with ascocarps that are capitate or clavate, has been treated in previous papers (Mains 1954, 1955). The Cudonieae, as discussed here, has ascocarps that are pileate. Imai (1941) has treated these taxa as subfamilies, Geoglossoideae and Cudonioideae, and has recognized a third subfamily, the Hemiglossoideae, for one genus Hemiglossum, which has branched coralloid ascocarps with unilateral hymenia. This genus has not been reported for North America. The genera of the Cudonieae appear to occupy positions intermediate between the Geoglosseae and the Helotiaceae. Leotia has multiguttulate ascospores (Fig. 3) similar to those found in Microglossum of the Geoglosseae but the structure of its ascocarps differs from that of all of the other genera of the Geoglossaceae. The ascocarps consist of a central tissue of gelatinous hyphae separated from an outer layer of gelatinous hyphae by a distinct layer of non-gelatinous hyphae (Figs. 2, 8). This is a structure which is found in Ombrophila and Ascotre