Flora of New Zealand Series

≡Bacidia perparva Zahlbr. in A. Zahlbruckner, K. Keissler & H.H. Allan, Trans. N. Z. Inst. 59: 311 (1928).

Holotype: New Zealand. Wellington, Feilding [Kitchener Park], rainforest on leaves of Podocarpus spicatus, H.H. Allan – W.

Description : Thallus crustose, continuous, irregularly granular, in irregular patches to several mm diam., greyish to green-grey. Photobiont a species of Chlorococcales, cells globose, to 17 μm diam. Apothecia sessile, blackish, rounded, epruinose, plane or convex, 70–250 μm diam., 50–90 μm tall, scattered or confluent. Hymenium I+ red, K/I ±blue, 30–50 μm tall, colourless; epithecium brown, to 10 μm thick. Hypothecium brown to 35 μm thick. Paraphysoids, 1–2 μm wide, septate, branched and anastomosing. Asci fissitunicate, clavate, 30–48 × 13–19 μm, lateral walls thin, K/I+ faintly blue, endoascus strongly thickened above, with a broad ocular chamber and a tiny, K/I+ faintly blue ring structure present; asci surrounded by a thin gelatinous layer reacting I+ red, I/K+ blue. Ascospores colourless, obovoid with rounded ends, 1-septate, septum supra-to sub-median, upper cell wider, not or slightly constricted at septum, smooth, with or without a thin gelatinous sheath, 11–17(–18) × 4–6 μm.

N: Known only from the type locality, but probably more widely distributed. Assumed by Matzer (1996: 176–177) to colonise bark as well as leaves.

Endemic

Illustration : Matzer (1996: 174, fig. 100).

Arthonia perparva is characterised by: the foliicolous (rarely corticolous) habit; the granular, greyish to grey-green thallus; adnate, rounded, sharply delimited blackish, epruinose apothecia; a brown hypothecium: I+ and K/I+ structures in the tholus; and colourless, obovoid, 1-septate ascospores. It is related to A. microsticta Vain. (Matzer 1996: 177).