Both fungus and host are endemic; it is known only from a single collection.

Type: Foliicolous Fungi; Description: Ascomata thyriothecial, scattered, superficial, circular, dark brown with a much paler margin, up to 0.3 mm in diameter, covered with a thin pellicle of wavy, reticulate hyphae; on the upper surfaces of leaves. Asci globose, 15–18 μm in diameter. Ascospores broadly clavate, 1-septate, 10–12 × 4–5 μm, smooth, dark brown.

Distribution: Wellington.; 1st Record: Hansford (1954).

Significance: None.; Host(s): Knightia excelsa.

The thyriothecia are completely superficial, epiphyllous, thin, flat, dark brown, circular, up to 280 µ diam., the wide margin much paler and consisting of very pale yellowish-brown wavy-reticulate hyphae about 2-3 µ wide, indistinctly septate, in a single layer, agglutinate to form a pellicle which extends over the whole ascoma, becoming darker towards the centre. Here it covers a rather loose weft of tangled hyaline hyphae 2 µ thick, much branched, in which the asci are embedded singly, though rather closely, apparently each in its own "locule". The asci are globose, sessile, thin-walled, 15-18 µ diam., 8-spored. Spores conglobate to nearly parallel, clavulate, 1-septate, slightly constricted, becoming dark brown when fully mature, 10-12 x 4.5-5 µ, the upper cell wider than the lower and subglobose, the lower slightly attenuate to the rounded base.

Thyriothecia superficialia, epiphylla, levia, applanata, brunneo-atra, orbiculata, usque ad 280 µ diam., margine pallidiora pelliculosaque. Mycelium liberum nullum. Asci in textu laxo hypharum hyalinarum singulariter subdenseque immersi sub pellicula myceliale, globosi, tenuiter tunicatae, 15-18 µ diam., 8-spori, sessiles. Sporae conglobatae vel subparallelae, clavulatae, 1-septatae, leves, brunnescentes, 10-12 x 4.5-5 µ.

Formerly this would have been placed in Eremotheca, but this genus is now considered not to be sufficiently distinct from Microthyriella.

Hab. in foliis Knightiae excelsae, Kapiti Is., Wellington, New Zealand, leg. H. H. Allan, November 1936.