Mycogloea orthospora (H. Sydow) McNabb ex Dingley, comb. nov.
Microcera orthospora H. Sydow, Ann. Mycol. 22: 317. 1924.
Fusarium orthoconium Wollenweber, Fus. Autogr. Del., Ed. 2, 637. 1926, non Fusarium orthosporum Sacc. in Saccardo & P. Sydow, Syll. Fung.16: 1100. 1902.
Fusarium microcera Bilai var. orthoconium (Wollenw.) Bilai, Fusarii 293. 1955.

Basidiocarp pustulate, 0.5-3 mm diam. x 0.5-1 mm high, vinaceous pink, translucent, gelatinous when fresh, drying ochraceous, in groups of up to 6; entire basidiocarp of homogeneous, hyaline, thin-walled septate hyphae 2-4 µm diam.; simple clamp connections present in basal hyphae, probasidia arising from basal hyphae; hymenium amphigenous, composed of a compacted layer of metabasidia and occasional filamentous dikaryophyses. Metabasidia cylindri]cal, 40-70 x 3-4 µm, with rounded apical cells, usually 3-septate, sometimes slightly constricted at septa, readily detached from a thin walled, cylindrical, 1-2 µm diam. subbasidial cell. Basidiospores not seen. Dikaryophyses filamentous, rarely branched, up to 2 µm thick, often up to 200 µm long.

Microcera orthospora was originally described and illustrated from New Zealand by Sydow (1924). Wollenweber (1926), in rejecting Microcera Desm., transferred the species to Fusarium with the new name F. orthoconium Wollenweber because the epithet orthosporum was already occupied in Fusarium (Saccardo & P. Sydow, 1902). Bilal (1977) treated the species as a variety of Fusarium microcera Bilai.

Fusarium orthoconium is generally not included in the modern treatments of Fusarium (Booth, 1971; Nelson et al., 1983). Gerlach and Nirenberg (1982) regarded the species as doubtful and published a translation of Wollenweber's diagnosis and illustration (Wollenweber, 1943; Wollenweber & Reinking, 1935).

Reexamination of the isotype specimen of Microcera orthosporum has shown it not to be typical of Fusarium. The late Dr. Ross McNabb, who also recollected this fungus and compared the recent collections to the isotype specimen, suggested that it is a species of Mycogloea Olive (Auriculariales). The so-called Fusarium conidia are, in fact, deciduous metabasidia. Unfortunately, McNabb never published his findings. Accordingly, the species is recombined in Mycogloea.

The fungus appears to be parasitic on a pyrenomycete stroma. It could be a synonym of Mycogloea macrospora (Berk. & Br.) McNabb but unfortunately no material of this species was available for examination.