The Gnomoniaceae are characterized by ascomata that are generally immersed, solitary, without a stroma, or aggregated with a rudimentary stroma, in herbaceous plant material especially in leaves, twigs, or stems, but also in bark or wood. The ascomata are black, soft-textured, thin-walled, and pseudoparenchymatous with one or more central or eccentric necks. The asci usually have a distinct apical ring. The Gnomoniaceae includes species having ascospores that are small, mostly less than 25 µm long, although some are longer, and range in septation from non-septate to one-septate, rarely multi-septate. Molecular studies of the Gnomoniaceae suggest that the traditional classification of genera based on characteristics of the ascomata such as position of the neck and ascospores such as septation have resulted in genera that are not monophyletic.

In this paper the concepts of the leafinhabiting genera in the Gnomoniaceae are reevaluated using multiple genes, specifically nrLSU, translation elongation factor 1-alpha (tef1-a), and RNA polymerase II second largest subunit (rpb2) for 64 isolates. ITS sequences were generated for 322 isolates. Six genera of leaf-inhabiting Gnomoniaceae are defined based on placement of their type species within the multigene phylogeny. The new monotypic genus Ambarignomonia is established for an unusual species, A. petiolorum. A key to 59 species of leaf-inhabiting Gnomoniaceae is presented and 22 species of Gnomoniaceae are described and illustrated.

Studies in Mycology No. 62: Leaf-inhabiting genera of the Gnomoniaceae, Diaporthales

Materials and methods

Collection and observation of herbarium specimens
Culture preparation and morphology
Measurements and data management
DNA amplification and sequencing
Phylogenetic analyses

Results and discussion

Phylogenetic analyses
Revised concepts of accepted genera
Evaluation of morphological and host characteristics

Taxonomy

Key to the species of Gnomoniaceae in this study

Descriptions of genera and species of the Gnomoniaceae

GNOMONIA

Gnomonia gnomon
Gnomonia alnea

New and revised species of Gnomonia

Gnomonia incrassata
Gnomonia monodii
Gnomonia neognomon
Gnomonia orcispora .
Gnomonia ostryae
Gnomonia pendulorum
Gnomonia rodmanii
Gnomonia skokomishica
Gnomonia virginianae

Additional species accepted in Gnomonia

Gnomonia amoena
Gnomonia arnstadtiensis
Gnomonia carpinicola
Gnomonia pseudoamoena

AMBARIGNOMONIA

Ambarignomonia petiolorum

APIOGNOMONIA

Apiognomonia veneta

Additional species of Apiognomonia

Apiognomonia acerina
Apiognomonia borealis
Apiognomonia errabunda
Apiognomonia hystrix

GNOMONIOPSIS
Type species of Gnomoniopsis

Gnomoniopsis chamaemori

New and revised species of Gnomoniopsis

Gnomoniopsis clavulata
Gnomoniopsis paraclavulata

Additional species accepted in Gnomoniopsis

Gnomoniopsis comari
Gnomoniopsis fructicola
Gnomoniopsis macounii
Gnomoniopsis racemula
Gnomoniopsis tormentillae

OPHIOGNOMONIA
Type species of Ophiognomonia

Ophiognomonia melanostyla

New species of Ophiognomonia

Ophiognomonia balsamiferae
Ophiognomonia pseudoclavulata
Ophiognomonia vasiljevae

Additional species accepted in Ophiognomonia

Ophiognomonia alni-viridis
Ophiognomonia gei-montani
Ophiognomonia intermedia
Ophiognomonia ischnostyla
Ophiognomonia leptostyla
Ophiognomonia micromegala
Ophiognomonia nana
Ophiognomonia padicola
Ophiognomonia rosae
Ophiognomonia rubi-idaei
Ophiognomonia sassafras
Ophiognomonia setacea
Ophiognomonia trientensis

PLAGIOSTOMA
Type species of Plagiostoma and synonymous genus, Cryptodiaporthe

Plagiostoma euphorbiae
Plagiostoma aesculi

New species of Plagiostoma

Plagiostoma barriae

Additional species accepted in Plagiostoma

Plagiostoma amygdalinae
Plagiostoma devexum
Plagiostoma euphorbiaceum
Plagiostoma euphorbiae-verrucosae
Plagiostoma fraxini
Plagiostoma geranii
Plagiostoma petiolophilum
Plagiostoma rhododendri
Plagiostoma robergeanum
Plagiostoma salicellum