The newly discovered systematic placement of
Bactrodesmium abruptum
, the lectotype species of the genus, prompted a re-evaluation of the traditionally broadly conceived genus
Bactrodesmium
. Fresh material, axenic cultures and new DNA sequence data of five gene regions of six species, i.e.
B. abruptum
,
B. diversum, B. leptopus
,
B. obovatum
,
B. pallidum
and
B. spilomeum
, were studied.
Bactrodesmium
is a strongly resolved lineage in the
Savoryellales
(
Sordariomycetes
), supported by Bayesian and Maximum Likelihood methods. The genus
Bactrodesmium
is emended and delimited to hyphomycetes characterised by sporodochial conidiomata, mononematous often fasciculate conidiophores, holoblastic conidiogenesis and acrogenous, solitary, dry, pigmented, transversely or rarely longitudinally septate conidia. The conidia are seceding rhexolytically, exhibiting multiple secession patterns. An identification key to 35 species accepted in
Bactrodesmium
is given, providing the most important diagnostic characters. Novel DNA sequence data of
B. longisporum
and
B. stilboideum
confirmed their placement in the
Sclerococcales
(
Eurotiomycetes
). For other
Bactrodesmium
, molecular data are available for
B. cubense
and
B. gabretae
, which position them in the
Dothideomycetes
and
Leotiomycetes
, respectively. All four species are excluded from
Bactrodesmium
and segregated into new genera,
Aphanodesmium
,
Gamsomyces
and
Kaseifertia
. Classification of 20 other species and varieties not recognised in the genus is discussed. Based on new collections of
Dematiosporium aquaticum
, the type species of
Dematiosporium
, the genus is emended to accommodate monodictys-like freshwater lignicolous fungi of the
Savoryellales
characterised by effuse colonies, holoblastic conidiogenous cells and dictyosporous, pigmented conidia with a pore in each cell. Study of additional new collections, cultures and DNA sequence data revealed several unknown species, which are proposed as taxonomic novelties in the
Savoryellales
and closely related
Pleurotheciales
.
Ascotaiwania latericolla
,
Helicoascotaiwania lacustris
and
Pleurotheciella erumpens
are described from terrestrial, lentic and lotic habitats from New Zealand and France, respectively. New combinations are proposed for
Helicoascotaiwania...