Catenularia Grove, Syll. fung. 4: 303. 1886.

Reblova, Martina, Nekvindova, Jana & Miller, Andrew N., 2021, Phylogeny and taxonomy of Catenularia and similar fungi with catenate conidia, MycoKeys 81, pp. 1-44 : 1

Catenularia Grove, Syll. fung. 4: 303. 1886.

Psiloniella Synonyms. Psiloniella Costantin, Mucéd. Simpl.: 25, 190. 1888.

Haplochalara Linder, Mycologia 25: 347. 1933.

Type species.

Catenularia cupulifera (Berk. & Broome) Réblová & A.N. Mill.

Emended description.

Colonies effuse, hairy to velutinous, brown, dark brown to black, mycelium partly immersed, partly superficial; composed of conidiophores, capitate hyphae and sometimes ascomata. Anamorph. Conidiophores macronematous, mononematous, solitary or in tufts, with dark stromatic hyphal cells around the bases, erect, straight or flexuous, unbranched, brown to dark brown, thick-walled, paler and thinner-walled towards the apex. Capitate hyphae scattered among the conidiophores, occasionally absent, erect, brown, extending percurrently, paler towards the apex, apical cell sterile, thin-walled, subhyaline to hyaline, slightly swollen, broadly rounded with a hyaline mucilaginous cap that may disappear with age. Conidiogenous cells integrated, terminal, monophialidic, extending percurrently, cylindrical, subcylindrical or somewhat lageniform, brown, conidia produced successively; collarettes cup- or funnel-shaped, brown, smooth or slightly roughened, margin entire or frayed. Conidia cuneiform, obclavate, rounded-obconic to broadly obovoid in side view, with an angular outline when viewed from above with 3-6 blunt corners, broadly rounded to flattened at the apex, truncate at the distinctive, hyaline basal hilum, with a small, circular, thin-walled, pore-like area visible in the cell wall at each corner, sometimes with a visible central pore at the base, aseptate, hyaline when young, fuscous, fulvous, brown to dark brown at maturity, thick-walled, smooth; formed singly, adhered in basipetal chains, occasionally in clusters. Teleomorph. Ascomata perithecial, non-stromatic, superficial, globose, subglobose to conical, papillate, glabrous occasionally with a powdery layer that disappears with age, sometimes covered with conidiophores and capitate hyphae. Ostiolar canal periphysate. Ascomatal wall carbonaceous, two-layered. Paraphyses persistent, branching, anastomosing, hyaline, longer than the asci. Asci unitunicate, short-stipitate, apical annulus non-amyloid, with eight ascospores. Ascospores fusiform, transversely septate, hyaline, smooth, without mucilaginous sheath or appendages.

Habitat and geographical distribution.

Saprobe on decaying bark, wood and bamboo culms of various hosts. Members of Catenularia have a worldwide distribution in temperate, subtropical and tropical geographic areas.

Notes.

Hughes (1965) considered capitate hyphae to be an important diagnostic characteristic of Catenularia . These structures have long escaped attention, and mycologists began to notice them only after they were described by Hughes (1949). We studied holotype material of several species and original descriptions and illustrations to examine and trace this character in Catenularia . Capitate hyphae have not been mentioned in the original descriptions of C. cupulifera ( Berkeley and Broome 1871; Richon 1877; Grove 1886). In studying collections of this species, we observed a variation in the presence of capitate hyphae. In some specimens, capitate hyphae are abundantly present, but may be scarce and difficult to find in others. Revision of the holotypes of C. cuneiformis var. minor ( Holubová-Jechová 1983) and Ch. trianguloconidia ( Réblová and Seifert 2003) not only revealed that both fungi are conspecific, but also led to the discovery of capitate hyphae, although they were not mentioned in the protologues of either species. They are scattered among conidiophores and easy to overlook. Phylogenetic analysis of several Catenularia representatives with capitate hyphae ( C. cubensis and C. minor ) and those without them ( C. angulospora , C. catenulata ) provided compelling evidence to consider these species congeneric.

In this study, we present a taxonomic circumscription of Catenularia using molecular and phenotypic data. The generic concept has been emended and species with and without capitate hyphae are accepted in Catenularia . We were unsuccessful in obtaining C. cupulifera into axenic culture from fresh material. The available non-type strain CBS 419.80 of this species is a contaminant (In the Blast search, ITS and 28S sequences derived from this strain showed 100% identity with sequences of various strains of Calycina citrina .). Eleven species are accepted in Catenularia and listed below, four of which have been verified with molecular DNA data. Other species are accepted based on morphological similarity, but have to be confirmed as members of Catenularia by molecular data. So far, the teleomorph has been observed in C. cubensis , C. cupulifera , C. minor and C. novae-zelandiae . Catenularia variegata ( Li et al. 2017) is excluded from Catenularia and transferred to a new segregate genus Fuscocatenula in this study. Disposition of Catenularia and morphologically similar taxa previously attributed to the genus is presented in Table 1 .

Haplochalara ( Linder 1933) and Psiloniella ( Costantin 1888) are accepted as generic synonyms of Catenularia . The systematic placement of H. pidoplitschkoi ( Litvinov 1967) is unknown. The species was characterised by dematiaceous, erect, simple conidiophores producing ellipsoidal, hyaline conidia that accumulate in slimy droplets and formation of dark chlamydospores in culture. Based on these characteristics, the species shows affinity to Chloridium ( Gams and Holubová-Jechová 1976) and would be better placed in this genus.