Flora of New Zealand Series

≡Polycornum rubrofuscum Malcolm & Vězda, Folia Geobot. Phytotax. Praha 30: 91 (1995). nom. inval. [Art. 43.1]

Polycornum rubrofuscum. Holotype: New Zealand. Nelson, Sharland Creek track, on Polystichum richardi, 130 m, 13.ix.1993, W. Malcolm 1123. CHR 413963. Isotype. Herb. A. Vězda.

Description : Thallus epiphyllous, very thin, greyish green, somewhat translucent, without a prothallus. Photobiont Phycopeltis, with radiating rectangular cells forming a thallus of continuous plates. Perithecia minute, globose, 0.25–0.30 mm diam., rusty, reddish brown, covered with copious filiform, pale red-brown appendages, appearing as a fuzzy covering (×10 lens). Wall red-brown on the outside, c. 15 μm thick, intense-red in K. Appendages simple, 100–120 m long, 5–8 μm thick, forming ±erect horns, composed of single, moniliform hyphae, cells globose, 3–5 μm thick, lateral walls thickened to 3 m thick. Internal walls of perithecia colourless, unchanged in K. Asci cylindrical-fusiform, walls uniformly thin, 8-spored. Ascospores ellipsoidal-fusiform, colourless, thin-walled, 3-septate, 16–20 × 4 μm.

S: Nelson to Otago (Leith Saddle Mt Cargill). On fern fronds (especially old Blechnum fronds) together with other foliicolous taxa such as Badimiella sérusiauxii and Fellhanera bouteillei. Probably much more widely distributed than records show at present, but its extremely small size makes it very easily overlooked.

Endemic

Illustrations : Malcolm & Vězda (1995c: 92, fig. 1); McCarthy & Malcolm (1997: 5, fig.2); Malcolm & Galloway (1997: 137 (2), 164, 187); Malcolm & Malcolm (2000: 11; 2001: 37, 53) – all as Polycornum rubrofuscum.

Porina rubrofusca is characterised by: the foliicolous habit; and the minute, horn-like appendages that grow thickly from the entire perithecial surface, making it appear tomentose. Polycornum was described as an apparently endemic monospecific genus in the family Trichotheliaceae similar to both Porina and Trichothelium, but differing in having complex, horn-like appendages (hence the genus name) developing from the entire surface of its perithecia, giving them a minutely tomentose appearance (Malcolm & Vězda 1995c). Harris (1995: 175) however, considered that Polycornum should be incorporated into Segestria Fr., opining that "I do not regard the setose ascomata of Polycornum sufficient to define a genus". McCarthy & Malcolm (1997:55, fig. 2) affirm the distinctness of the moniliform chains of thick-walled cells comprising the perithecial appendages of Polycornum, and that they provide "a compelling argument for its continued recognition". Recently, Lücking (2003: 41) reported that Polycornum should be considered as synonymous with Porina and combined it in Porina (Lücking 2004a: 418). However, in his catalogue of the Porinaceae, Pat McCarthy (2003d) still accepts Polycornum as an independent entity.