ADDITIONAL SPECIMENS EXAMINED: NORTH ISLAND: AUCKLAND: Kawakawa Bay, on decorticated wood, 5 May 1983, G. J. Samuels, P. R. Johnston, T. Matsushima,&R. H. Petersen, PDD 45801, PDD 45802; Titirangi, Titirangi Beach Reserve, on decorticated wood, 24 Mar 1981, G. J. Samuels, B. Segedin, & H. Thiers, PDD 49612, anamorph on host; Waitakere Ranges, Kauri Grove Trail, on decorticated wood, 27 Nov 1980, G. J. Samuels, P. R. Johnston, &M. Rattray, PDD 62377, culture on CMD; Waitakere Ranges, Piha Valley, Winstone Trail, 18 Mar 1992, P. R. Johnston, PDD 60016. COROMANDEL PENINSULA: Little Barrier Island, Thumb Track, 500 ft, on Nothofagus truncata, 30 Aug 1958, J. M. Dingley, PDD 18638, culture on PDA, PDD 18639; Little Barrier Island, Thumb Track, 500 ft, on Coprosma arborea 30 Aug 1958, J. M. Dingley, PDD 18655, culture on PDA; Little Barrier Island, Shag Track, on Pittosporum umbellatum, 29 Aug 1958, F. J. Newhook, PDD 18642, culture on PDA; Little Barrier Island, Shag Track, 100 ft, on Pittosporum umbellatum, 29 Aug 1959, F. J. Newhook, PDD 18663; Little Barrier, Summit Track, 200 ft, on dead wood, Nov 1947, J. M. Dingley, PDD 16892; Little Barrier Island, on Dysoxylon spectabile, 28 Aug 1958, J. M. Dingley, PDD 18666; Thames, Waiomo, on Elaeocarpus dentatus, 26 Aug 1958, J. M. Dingley, PDD 18656*. NORTHLAND: Omahuta State Forest, Omahuta Kauri Sanctuary, on Agathis australis, 10 May 1981, G. J. Samuels & E. Horak, PDD 41967. AUCKLAND ISLANDS: Auckland Island, Port Ross, Beacon Point, on decort., rotten wood, 22 Mar 2000, P. R. Johnston, PDD 71829.

Subiculum evanescent, cream to light brown, with grey patches bearing conidiophores and, when very young, ascomatal initials can be seen, on some hosts developing under the epidermis, later erumpent. Stromata (400)563 ± 73(725) µm high, (550)760 ± 91.5(950) µm wide (n = 85), cylindrical to barrelshaped with flattened, disk-like top, 350-550 µm diam., often with discoid base, dark brown to black, shiny, solitary or crowded in small groups, sometimes 2-3 fused together, young stromata covered by the felty subiculum and progressively emerging during development until completely free at maturity; sometimes additionally covered by host epidermis, thus appearing white. Ostioles finely to coarsely papillate. Ectostroma 50-75(100) µm thick, black. Entostroma initially white, then cream, brown, absent in mature material. Perithecia detached and collapsed in mature material. Ascus apical rings (1)2 ± 0.4(2.8) µm high (n = 41), upper width 2.4- 2.8 µm, lower width 1.9-2.8 µm, without bulge at upper margin, J+, pale blue. Ascospores (9.6)12.5 ± 1(16) µm long, (4.8)6.2 ± 0.6(9) µm wide (n = 385), inequilaterally ellipsoidal, brown to dark brown, with straight germ slit, typically extended to the entire length of the spore, but often situated closer at one end than at the other (Fig. 17H). Conidia 3- 4.5 x 2.5-3.5 µm.
Cultures on OA after 20 days at 20°C under diffused daylight with centre slightly raised, hyphae restricted, margin flat, white, some red pigment spreading, sterile. On CMD under same conditions, 1.5 cm diam., flat, appressed, without aerial mycelium, centre opaque, waxy, margin translucent, slightly orange, after 34 days 2 cm diam. After 24 days 2-2.5 cm, centre flat, compact, grey-green due to fruiting structures, outside loosely cottony, white. Conidiophores over 200 µm long, 2-3 µm wide, mononematous, unbranched or roughly dichotomously branched, smooth, subhyaline to pale tan towards base. Conidiogenous cells cylindrical, terminal and intercalary, geniculate with conspicuous, circular refractive frill at each point of conidial dehiscence. Conidia 3.5-4.5(6) x 2-3(4) µm (n = 43), subglobose to elliptical, rarely clavate, with protuberant, flat basal abscission scar bearing a minute frill, smooth, subhyaline. On PDA white to cream with large grey-brown areas bearing the conidiophores, felty, forming concentric rings, reverse light brown.
ANAMORPH: Geniculosporium.

HOSTS: Agathis australis, Coprosma arborea, Dysoxylon spectabile, Elaeocarpus dentatus, Nothofagus truncata, Pittosporum umbellatum.
MATRIX: Decorticated heavily decomposed wood, bark.

Subiculum evanescens, cremeum ad pallide brunneum, cum maculis cinereis conidiophora ferentibus. Stromata (400)563 ± 73(725) µm alta, (550)760 ± 91.5(950) µm lata, cylindracea ad doliformia apice applanato, disciformi 350-550 µm diametro praedita, atrobrunnea ad nigra, nitida, solitaria vel in parvis gregibus conferta, interdum 2- 3 connata, lanoso subiculo dum juvena tecta, paulatim dum evoluentia emergentia, libera omnino aetate provecta. Ostiola laeviter ad crasse papillata. Annulus apicalis asci (1)2 ± 0.4(2.8) µm altus, parte superiore 2.4-2.8 µm et inferiore 1.9-2.8 µm latus, margine superiore non protuberanti, iodo pallide coerulescenti. Ascosporae (9.6)12.5 ± 1(16) µm longae, (4.8)6.2 ± 0.6(9) µm latae, asymmetrice ellipsoideae, brunneae ad atrobrunneae, fissura germinativa recta, ad totam ascosporam recurrenti in ascospora asymmetrice locata praeditae. Statusanamorphosis Geniculosporium.

ETYMOLOGY: In honour of the New Zealand mycologist P. R. Johnston.
NOTES: Distinctive features of R. johnstonii are the flattened top of the stroma and the asymmetrical position of the germ slit on the ascospore. It is closer o one spore end and more distant towards the other (Fig. 17H). The subiculum can be observed only in young material. At first sight, this species may be confused with Astrocystis spp. However, it clearly belongs to Rosellinia as young stromata develop in a subiculum and the anamorph belongs to the form genus Geniculosporium, contrary to Astrocystis, in which the stromata break through the host epidermis and may split in a stellate manner, and the anamorphs belong to form genus Acanthodochium (Ju & Rogers 1990; Læssøe & Spooner 1994). The anamorph in culture differs from the one of R. communis by more frequent intercalary conidiogenous areas having more loci.
Rosellinia johnstonii also resembles R. mammoidea, but it has smaller, narrowly ellipsoidal ascospores with an asymmetrical germ slit and larger stromata with flattened discoid-like tops. The stroma and ascospore sizes are statistically significantly different, as shown by the 65% confidence ellipses (Fig. 9C) and the discriminant analysis (data not shown). R. subiculata (Schw.) Sacc. has slightly smaller ascospores than R. johnstonii. These two species also differ from each other with respect to subiculum, stroma shape, and germ slit (Petrini 1993).

HOLOTYPUS (hic designatus): New Zealand, North Island, Auckland: N of Kaukapakapa, vic. Glorit, Atuanui State Forest, Mt Auckland, on bark, 11 Sep 1980, G. J. Samuels & P. R. Johnston, PDD 49674, culture and anamorph on CMD. PARATYPUS (hic designatus): North Island, Northland: Hokianga Co., Waipoua State Forest, vic. Forest Headquarters, on decorticated wood, 29 May 1982, G. J. Samuels, H. P. Hawthorne, P. R. Johnston, & R. H. Petersen, PDD 43197, anamorph on host, on CMD, cultures on OA, CMD.