Flora of New Zealand Series

≡*Phymatopsis dubia Linds., Trans. Roy. Soc. Edinb. 24 (2): 442 (1866).

Holotype: New Zealand. Otago, Dunedin, Pelichet Bay, in the bush on Usnea sp. (apothecia), 17.xii.1861, W.L. Lindsay – E.

Description : Lichenicolous, infecting apothecial disc of host, the infected parts becoming discoloured and brownish. Conidiomata pycnidial, immersed in the hymenium of the host, only the ostiole sometimes slightly protruding above the level of the epithecium, scattered to loosely aggregated, sometimes almost confluent, subglobose, 25–60 μm diam., ostiolate; wall mainly 1–3 layers of cells thick, mostly 3–3.5 μm thick but to 8 μm near ostiole, cells pseuedoparenchymatous, subglobose to somewhat polyhedral, subhyaline except close to ostiole and there thick-walled and golden-brown, mainly 2–3 μm diam. Conidiogenous cells arising from inner wall of the pycnidium, short-ampulliform to obpyriform, hyaline, smooth-walled, phialidic, not proliferating, 4–8 × 3–5 μm. Conidia abundant, narrowly ellipsoidal to almost bacillar, sometimes slightly truncated at the base, hyaline, simple, 0–2-guttulate, smooth-walled, 3.5 × 1.5–2 μm.

S: Otago. Known only from the type collection.

Endemic

Host : Usnea sp. [Lindsay (1866b: 442) records it as Usnea barbata var. florida, but it is likely that the material refers to U. tenerior Nyl.]

Illustrations : Lindsay (1866b: pl. LXI, figs 29–32 – as Phymatopsis dubia; 1866c: pl. XXX, figs.36–41 – as P. dubia); Hawksworth (1981: 53, fig. 26).

* Phoma dubia is characterised by: the lichenicolous habit; the immersed pycnidia in the apothecial discs of the host (Usnea sp., causing a brownish discolouration); and the minute, ellipsoidal to subbacillar conidia, 3.5 × 1.5–2 μm.