Capnodiaceous sooty mold phylogeny

Sequences from the 18s rDNA gene of representatives of the capnodiaceous sooty mold families Antennulariellaceae, Capnodiaceae, and Metacapnodiaceae as well as 14 ascomycete taxa representing the Plectomycetes, Dothideales, Pyrenomycetes, and Pleosporales, and yeast outgroups were analyzed. Sooty mold capnodiaceous ascomycetes comprising were found to be a monophyletic group, the Capnodiales. The convergent origin of the bitunicate ascus associated with the periphysoid sterile element is validated. The major Capnodiales characters are the foliicolous habit, darkly pigmented hyphae, and a distinctive periphysoid sterile element associated with a fissitunicate type of bitunicate ascus.Key words: ascomycetes, Capnodiales, periphysoid sterile elements.

A new approach to the phylogeny of Euascomycetes with a cladistic outline of Arthoniales focussing on Roccellaceae

A phylogenetic working hypothesis of euascomycete relationships is presented. Paraphysoidal ascolocular fungi are monophyletic and ascohymenial fungi are paraphyletic as paraphyses are considered plesiomorphic and paraphysoids apomorphic within euascomycete fungi. As a result it is not necessary to postulate parallel evolution of the bitunicate ascus, and furthermore presence of paraphyses in the prototunicate caliciaceous fungi is no longer in conflict with paraphyses in ascohymenial fungi. A cladistic outline of the order Arthoniales with special focus on the Roccellaceae including 20 taxa and 92 characters is presented. The type species of all genera considered are used as terminal taxa. It is suggested that the type species of Arthothelium should be excluded from the order Arthoniales. The Arthoniaceae are paraphyletic as Arthonia radiata and Arthothelium spectabile form a grade pair. The family Roccellaceae is monophyletic and corroborated in its traditional sense, but some rearrangements within the family are made. Opegrapha vulgata and Lecanactis abietina form a pair, but the family Opegraphaceae is paraphyletic if the pair Chiodecton sphaerale and Schismatomma pericleum are included. The originally described ascoma of the species Darbishirella gracillima, Ingaderia pulcherrima, and Reinkella fragillima are found to be lichenicolous fungi. The mycobiont ascomata of Darbishirella gracillima produce 3- not 2-septate spores. No ascomata of the mycobionts of the two latter species have as yet been found. Key words: Euascomycetes, Arthoniales, Roccellaceae, phylogeny, cladistics, lichenicolous.

La paroi des asques chez les Pyrénomycètes : étude ultrastructurale. I. Les asques bituniqués typiques

A complex and homogeneous organization is present in the ascus wall of typical bitunicate Pyrenomycetes. First unitunicate, the wall soon becomes bitunicate. A clear space then separates both tunicae (exoascus and endoascus); it is formed by the lysis of the external part of the endoascus. In the mature ascus the exoascus is composed of two superposed layers and the endoascus of a single layer which shows remarkable accordion-like fibrillas.The essential structural feature of the bitunicate ascus wall is the presence, in the Pyrenomycetes as well as in lichenized and nonlichenized Discomycetes, of two tunicae, the inner (endoascus) presenting a wavy or folded fibrillar structure. In the Pyrenomycetes such a structure is much more distinct, however; a clear space in addition separates the exoascus and the endoascus.

Asci of the Pezizales. VI. The apical apparatus of Morchella esculenta, Helvella crispa, and Rhizina undulata. General discussion

Morphological, developmental, and cytochemical examinations were made with light and electron microscopy on the apical apparatuses of Morchella esculenta, Helvella crispa, and Rhizina undulata, all species with large, stipitate apothecia. Ascus tips in R. undulata were markedly thinner walled than the rest of the ascus, while those in M. esculenta and H. crispa were slightly thinner than the rest of the ascus wall. Lipid bodies were detected in developing asci of H. crispa and M. esculenta. Their unique occurrence in asci of members of the Morchellaceae and Helvellaceae may have taxonomic significance. With the electron microscope, opercula were distinguished cytochemically in all three species. In H. crispa and M. esculenta dehiscent zones were found to be restricted in the inner layer of the ascal wall. Characters of the apical apparatuses of H. crispa and M. esculenta suggest greater taxonomic relatedness between these species than with any other operculate group. The apical apparatus of R. undulata differed notably from the other species.The present series of studies has demonstrated distinct variability of the operculate ascus and its apical apparatus in morphology, cytochemistry, and development. Several major forms of the apical structures were observed. These examinations support the chemotaxonomic and cytological investigations on representatives of the Pezizales made previously by Arpin and Berthet. Outside of the Thelebolaceae, members of the Pezizales are chiefly characterized by the operculate dehiscence of their asci. Members of the Thelebolaceae eject their spores through a variety of dehiscent mechanisms. Present examinations of those representatives of the Thelebolaceae with functionally operculate apparatuses, i.e., Lasiobolus and Coprotus, support their transferrance to the Pyronemaceae. Taxa which form nonoperative opercula, i.e.,Ascozonus and Trichobolus, also show closer affinities with the Pyronemaceae than with the nonoperculate representatives of the Thelebolaceae. The nonoperculate members of the Thelebolaceae apparently do not belong in the operculate Discomycetes. The operculate ascus wall is structurally compared with the pored and bitunicate ascus walls. The terms 'bitunicate' and 'unitunicate' are redefined.

LAYERED STRUCTURE IN THE BITUNICATE ASCUS

The bitunicate ascus of Botryosphaeria piceae Funk was found to have a multilayered structure of the endotunica, the hydrophylic, extensible, inner wall of the ascus that functions in ascospore discharge. A similar multilayered endotunica was observed in Botryosphaeria quercuum (Schw.) Sacc. and in Pleospora herbarum (Fr.) Rab. var. herbarum following treatment in 7% KOH solution.