Anguillospora, the second largest genus of aquatic hyphomycetes, is phylogenetically diverse. The type species, A. longissima, is a member of the Pleosporales and is a now accepted as a synonym of the type species of Amniculicola, with this latter genus recommended for protection over Anguillospora (Rossman et al. 2016). Several species placed in Anguillospora belong in Leotiomycetes, including at least two in the Tricladiaceae, “A.” crassa and “A.” furtiva. The Anguillospora species in Tricladiaceae all have thalloblastic percurrent conidiogenous cells and sigmoid conidia with schizolytic secession. Specimens identified as A. crassa that have ITS sequences deposited in GenBank appear to represent several different species (Fig. 2). An authentic specimen of “A.” furtiva (GenBank AY148107, CCM F-20483, cited in Descals et al. 1998) is phylogenetically similar to one of the “A.” crassa clades (Fig. 2). However, which of the putative “A.” crassa specimens phylogenetically matches the type, collected from the United Kingdom (Ingold 1958), is not known and epitypification is needed to resolve the taxonomy of this genus.

Anguillospora specimens have often been linked to a sexual state, and some of these have been referred to Leotiomycetes genera Pezoloma (Descals et al. 1998) and Mollisia (Webster 1961). Neither of these sexual genera are accepted as Tricladiaceae (Johnston et al. 2019). Based on published descriptions, the Pezoloma and Mollisia species linked to Anguillospora have an apothecial morphology similar to that illustrated for Spirosphaera (see https://scd.landcareresearch.co.nz/Specimen/PDD_117564); also see Discussion.

Digby & Goos (1987) reported an Anguillospora asexual state grown from germinated ascospores from the type specimen of Loramyces juncicola. This was accessioned as ATCC 46458 and according to the ATCC web pages its genome was sequenced by JGI (https://www.atcc.org/products/all/46458.aspx#characteristics). Data from this genome was included in the analyses of Johnston et al. (2019) that showed Loramyces belongs in a monophyletic clade together with Mollisia (Mollisiaceae), phylogenetically distant from Tricladiaceae.

An aquatic hyphomycete genus with conidia comprising loosely interwoven, branched, septate coils. The ex-type specimen of the type species Spirosphaera floriformis (GenBank NR_138376, CBS 405.52) belongs in the Tricladiaceae, but only rDNA sequences are available (Fig. 2). An unnamed species from New Zealand has an asexual state with a Spirosphaera-like morphology (Fig. 2), is known from both its asexual (e.g., https://scd.landcareresearch.co.nz/specimen/ICMP%2020907) and sexual states (e.g., https://scd.landcareresearch.co.nz/Specimen/PDD_117564), and appears to be common on wood in forest streams. Whether this New Zealand species is congeneric with S. floriformis needs additional genes to resolve.

Note that Ekanayaka et al. (2019) placed Spirosphaera in their Trizodia-Calloriopsis clade, but they represented this genus by a specimen identified as S. minuta, a specimen phylogenetically distant to the ex-type specimen of the type species, S. floriformis (unpubl. data) (Table 2).

The name of the type species, Tricladium splendens, has been used for several GenBank accessions. Several of these specimens have multiple genes available and clearly belong in Tricladiaceae. Tricladium, the largest genus of aquatic hyphomycetes, is polyphyletic across Leotiomycetes (Campbell et al. 2009). Specimens identified as species in this genus are likewise spread across the Tricladiaceae phylogeny (Fig 2). These include ex-type specimens for T. obesum (GenBank KC834068, CCM F-14598) and T. terrestre (GenBank NR_160144, CBS 697.73).

The Tricladium species in Tricladiaceae all have dark colonies but conidiogenesis is variable, percurrent in T. splendens and T. obesum, sympodial in T. castaneicola (Tricladiaceae based on LSU sequences, Campbell et al. 2009) and T. terrestre, or determinate in T. indicum, and this perhaps reflects the polyphyletic nature of the genus as currently accepted in a morphological sense.

The sexual morph of T. splendens was described as Hymenoscyphus splendens (Abdullah et al. 1981). Based on the description of Abdullah et al. (1981), it is morphologically similar to the sexual morph of other Tricladiaceae.