Proliferodiscus in New Zealand [P.R. Johnston, September 2026]

[see also the image of the ITS based phylogeny, plus accompanying notes]

Proliferodiscus dingleyae, described from Nothofagus bark from New Zealand, is the only named Proliferodiscus species reported from New Zealand, although Johnston et al. (2012, Fungal Biology 116: 401-412) reported another unnamed species detected in cultures grown from symptomless Nothofagus leaves. Based on ITS sequencing from specimens collected over the past 25 years, there appear to be several Proliferodiscus species on wood of native and exotic plants in New Zealand (Clades 1-4 in the accompanying ITS-based phylogeny). Superficially they are macromorphologically similar to P. dingleyae, although several of the clades have apothecia with a dark coloured receptacle, compared to the pale coloured receptacle described for P. dingleyae. Based on microscopic features such as the presence or absence of croziers at the bases of the asci and hair morphology, the various clades can be distinguished morphologically. See key, notes on microscopic features and illustrations of hairs for some of the specimens in each of the clades, provided with the image of the ITS phylogeny.

Specimens in Clade 3 morphologically match an isotype specimen of P. dingleyae (PDD 18988), with characteristic strongly ornamented hairs, asci with croziers, pale coloured receptacle and bright yellow hymenium.

Several specimens from other parts of the world have ITS sequences very close to the New Zealand species. How their morphology compares, and whether they may provides names for some of the New Zealand clades, is not known.

The holotype collection was previously reported by Dennis (1961) as Dasyscyphus inspersus (Berk. & Curtis) Saccardo (= Proliferodiscus inspersus (Berk. & Curtis) Haines & Dumont). Though closely related to that species, it differs in having larger asci which lack a blue pore in Melzer's reagent, larger, less clavate spores and less flexuous hairs. However, the apothecia proliferate from the disc in the same fashion as those of P. inspersus, and are generally very similar in appearance. Proliferodiscus dingleyi differs from P. earoleucus (Berk. & Broome) Haines & Dumont, which similarly has an iodine negative ascus pore, in having larger asci and spores and in lacking the dense covering of strongly curled and interwoven hairs characteristic of that species. The apothecia of P. earoleucus commonly have multibranched stipes but evidently only infrequently proliferate from the disc.

Apothecia of P. dingleyi are structurally similar to those of the type of the genus, although the subiculum -like hyphae may be scarcely evident at maturity. Nevertheless, these hyphae can be observed in vertical section and are more obvious in young apothecia. The excipular tissue does exhibit a dextrinoid reaction, though this is somewhat inconstant and frequently indistinct.