Sparsa denudata. Peritheciis subglobosis, ad basin applanatis, atris glabris, nitidis. Ascis cylindraceis. Sporidiis ellipticis, continuis, brunneis (0.016-0.018 x 0.008 mm.).

On rotten wood. Wellington (Mt. Travers).

7166e263-e99c-460a-8f80-6e4d24808110

ADDITIONAL SPECIMENS EXAMINED: NORTH ISLAND: WELLINGTON: Days Bay, on dead wood, Mar 1925, D. W. McKenzie, PDD 2097; Days Bay, on dead wood, May 1947, J. M. Dingley, PDD 16891. AUCKLAND ISLANDS: Auckland Island, Erebus Cove, on decort. wood, 20 Mar 2000, H. Burdsall, PDD 71726, culture; Enderby Island, Sandy Bay, on Metrosideros robusta, 21 Mar 2000, P. R. Johnston, PDD 71830.

Subiculum evanescent, white, cream to light brown to grey. Stromata (350)482 ± 80(650) µm high, (500)658 ± 105(900) µm wide (n = 25), cylindrical to semiglobose, black, shiny, solitary or crowded in small groups, rarely 2-3 fused together. Ostioles finely papillate. Ectostroma 50-75 µm thick, black. Entostroma not seen. Perithecia detached in mature material. Ascus apical rings 2-3 µm high, upper width 2.8-4 µm, lower width 1.9-3 µm (n = 17), without bulge at upper margin, J+, blue. Ascospores (11)13 ± 1(16) µm long, (6.2)7.5 ± 0.5(9) µm wide (n = 150), inequilaterally ellipsoidal, brown to dark brown, with 8-10 µm long straight germ slit (Fig. 20G), some of them with a basal, 1 x 1 µm large, cellular appendage (Fig. 20G).
Culture on MA white, felty, grey areas with conidiophores. Conidia 3.5-5 x 3-4 µm.
ANAMORPH: Geniculosporium.

HOSTS: Metrosideros robusta, unidentified dicotyledonous wood.
MATRIX: Decorticated heavily decomposed wood.

NOTES: Rosellinia mammoidea is characterised by a cream to light brown subiculum present only in a very early state, and dark brown ascospores with rounded side walls with a germ slit about two thirds of their length. In the original description the ascospore size ranges from 16 to 18 x 8 µm (Cooke 1879). The Kew herbarium has three specimens labelled as R. mammoidea from the period when Cooke described the fungi from New Zealand (Cooke 1879). One originates from Wellington, collected by Travers, the second from the South Island, J. Kirk 72, the third from Waitaki, ex herb. M. C. Cooke. The Travers collection is cited by Cooke and is labelled as the type. The ascospore size in this specimen ranges from 11 to 14 x 6.5 to 8 µm, clearly much smaller than the dimensions given in the literature. The Kirk specimen is R. communis: its ascospores measure 16-21 x 8.5-10 µm. The third specimen has ascospores measuring 19-23 x 10-13 µm with a sigmoid germslit and is Helicogermslita aucklandica. At first sight, all three have similarstromata. The wrong ascospore size indicated in the literature was very likely the reason why most Rosellinia from New Zealand identified as R. mammoidea are actually R. communis.
Rosellinia mammoidea can be distinguished from R. communis by smaller stromata and smaller ascospores, and from R. johnstonii by smaller stromata with mostly rounded tops, larger (usually wider) ascospores, occasionally with a cellular appendage and shorter germ slits positioned symmetrically. The results of the discriminant analysis of the ascospore size indicated statistically significant differences among these three species, as also shown by the 65% confidence ellipses in Fig. 9C. The stromatal size was also statistically significantly different (data not shown). R. mammoidea differs also from R. subiculata (Schwein. : Fr.) Sacc. by the subiculum colour, larger ascospores, and a shorter germ slit (Petrini 1993).
Martin (1968) treated R. mammoidea as a synonym of Hypoxylon mastoideum (Fr.) P.M.D.Martin ( Rosellinia mastoidea (Fr.) Sacc.) and gave its spore size as 10-22 x 5-10 µm. Such a large variability in ascospore size is most likely the result of including more than one taxon in the species concept. According to Petrini (1993) its basionym, Sphaeria mastoidea Fr., remains doubtful. Martin (1968) drew his taxonomic conclusions mainly from material collected in South Africa. Based on my experience, the geographical distribution of most species of Rosellinia is restricted. Therefore, the New Zealand material, which originates from an isolated area, is almost certainly different from Sphaeria mastoidea which very likely originates from Europe. South African material still needs to be studied in order to establish its identity.

HOLOTYPUS: New Zealand, North Island, Wellington: on wood, Travers 308, Herb. Cooke 1885, K 69372.