Nothofagus fusca (Hook.f.) Oerst.Wellington. York Bay, 500 feet, Nov. 1921, E.H.Atkinson; Same Locality, 300 feet, June 1927, E.H.Atkinson.

Hymenophore annual, compound, composed of numerous pilei (5-46) arising from a common central or lateral freely branched stem, compact, coriaceous, to 20 cm. broad. Pilei coriaceous, 2-5 cm. x 1-3 cm. x 1-4 mm., fan-shaped, cuneiform, or spathulate; surface bay brown or tobacco brown, radiately striate and irregularly nodose, cuticle absent, replaced by imbricate hyphae with inflated rounded ends; margin acuminate, fringed, often undulate; hymenial surface decurrent, dingy bay brown to tobacco brown, dissepiments toothed, and deeply lacerate in old specimens. Context to 1 mm. thick, bay brown when fresh, drying fuscous, dense and gelatinized, of radiately arranged densely compacted parallel hyphae; skeletal hyphae 5-8 µ thick, wall 2-3.5 µ, freely branched, aseptate, contents staining; generative hyphae 3-6 µ thick, wall 1 µ, sparsely branched, septate, with large somewhat sparse clamp connections; associated with numerous lactiferous ducts which are 6-8 µ thick, linear or slightly irregular, staining deeply. Pores decurrent, bay brown or fuscous in section, 0.2-1 mm. deep, variable in size and shape, angular, 1-3 mm. long, to 1 mm. broad; dissepiments 125-400 µ thick, of densely compacted woven hyphae, tapering to the apex where even. Basidial type clavate, basidia linear-oblong or subclavate, to 24 x 6 µ. Spores globose or less often subglobose, 4-5 µ diameter, smooth, hyaline, abundant.

Growing on rotting wood and humus between large roots of living trees.

A feature of the species aiding diagnosis is the large compound hymenophore, which consists of numerous fan-shaped or spathulate pilei attached by irregular, freely branched, lateral stems. Plants grow to a large size, a specimen from Mt. Lofty, South Australia, kindly communicated by J.B.Cleland, weighing 7 lb. when fresh and measuring 13 in. x 11 in. x 10 in. The only other species in New Zealand with a similar growth habit is P. berkeleyi, which may be recognised readily by the large globose echinulate spores.

LOCALITY: Tarawera, New Zealand.

Hymenophore annual, compound, of numerous pilei (5-46) arising from a common central or lateral base, to 20 cm broad. Pilei flabelliform, cuneiform, or spatulate with narrow stem-like bases, 2-5 cm wide, 1-10 cm radius, 1-4 mm thick; pileus surface bay or tobacco brown, radiately striate, irregularly nodose; without a cortex; margin acute, fringed, often undulate, plane; hymenial surface dingy bay to tobacco brown, even or undulate. Pores decurrent, in section bay or fuscous, varying in size and shape, 1-3 mm long, to 1 mm broad and deep; dissepiments 120-400 µm thick, tapering, apices toothed. Context bay when fresh, drying fuscous; to 1 mm thick, of radiately arranged parallel hyphae densely compacted and cemented with mucilage; binding hyphae 5-8 µm diameter, walls 2-3 µm thick, freely branched, aseptate; generative hyphae to 6 µm diameter, walls to 1 µm thick, sparsely branched, septate, with clamp connections; conducting hyphae 6-8 µm diameter, walls 0.5 µm thick, scantily septate, contents staining. Hymenial layer to 25 µm deep, a close palisade of basidia and paraphyses. Basidia subclavate or subcylindrical, 18-24 x 5-6 µm, bearing 4 spores; sterigmata erect, slender, to 3 µm long. Paraphyses subcylindrical, 12-18 x 4-5 µm. Spores globose or less often subglobose, 4-5 µm diameter, walls smooth, hyaline, 0.1 µm thick.

Australia, New Zealand

Decayed wood and humus at bases of living trees, growing from mycelial masses.

In appearance plants somewhat resemble small cauliflowers, pilei of various shapes arising from a common stem, forming a dense rosette in which it is difficult to identify individual pilei. One specimen from the herbarium of J. B. Cleland, ex "South Australia, Mt. Lofty" measured 32 x 17 x 25 cm and when fresh weighed 15.4 kg. Pores are irregular in shape and size, most being linear, some irpiciform, others almost labyrinthiform. The species may be identified by the large irregular pores, large diameter skeletal hyphae, and globose smooth spores.

LOCALITY: Mt. Tarawera, Auckland

Type: Lignicolous Fungi; Description: Basidiomata annual, compound, consisting of numerous (5–45) pilei arising from a common central or lateral base and giving the fruiting body a cauliflower-like appearance, up to 200 mm wide, woody. Pilei fan-shaped or spatulate, with narrow stem-like bases, 20–50 mm wide, 1–4 mm thick. Pileus surface radiately striate, dark brown to purplish black, margin fringed, often undulate. Pore surface even or undulate, dark brown, pores large, irregular, 1 or less per mm. Context brown to blackish, 1 mm thick. Hyphal system dimitic. Basidiospores globose, 4–5 μm in diameter, smooth, hyaline.

Distribution: Auckland, Bay of Plenty, Wellington, Wairarapa, Nelson, Buller, Marlborough Sounds.; 1st Record: Berkeley (1855: as Polyporus colensoi).

Significance: The cause of a fairly common brown cubical butt rot in Nothofagus spp.; Host(s): Nothofagus fusca, N. solandri var. solandri, N. truncata.

[Notes from Kew Type specimen, PRJ 2010] Kew images.

In our work, Grifola colensoi spores are more elongate compared with Cunningham (1965) description (globose to sub-globose), and have thicker spore walls. The Australian samples also seem to have smaller pores than reported by Cunningham (1965), although it is possible his measurements are from fresh samples. As we could not check New Zealand specimens to compare with Australian ones, we cannot be definitive about differences between the two areas. Grifola colensoi is characterized by its large irregular pores, large diameter skeletal hyphae, and globose smooth spores.