ADDITIONAL SPECIMENS EXAMINED: NEW ZEALAND: AUCKLAND: Henderson, off Spragg's Hill Rd, on Dacrydium cupressinum, J. M. Dingley, Mar 1947, PDD 5391. BAY OF PLENTY: Opotiki, on Nothofagus truncata, G. B. Rawlings, 27 Nov 1951, NZFRI 1759. AUSTRALIA: VICTORIA: Ferntree Gully, Dandenong Range, D. Jones, 19 May 1965, K. TASMANIA: L. Rodway (K, holotype of Polyporus tasmanicus Massee 1899, non Berk. 1860).

BASIDIOCARPS annual, infundibuliform to convex arising from a contracted base or more broadly attached, margin down-curved, up to 5.5 cm across, 5 cm from base to margin, 8 mm thick; pileus surface wrinkled, light brown (57.1 Br) to brown (58.m.Br), glabrous except for numerous scattered agglutinated bundles of hyphae (appearing macroscopically as tiny spots) appressed or erect, to almost 1 mm long; pore surface yellowish brown (76.1y Br- 72.d.OY) except at margin where pores are more reddish (46.gy.r Br), or pores appearing resinous throughout and then darker reddish brown (20.d.gy.Red) contrasting with the pale context; pores angular to convoluted, tending to be radially arranged especially on ascending parts of contracted base, 1-2 per mm, with dissepiments sometimes fimbriate at edge, extending over whole surface of contracted base; tubes concolorous, rather brittle, especially when appearing resinous, to 3.5 mm long; context cream, homogeneous, to 5 mm thick, of loose texture; cortex of dense texture, brown, 100-200 µm thick. Pileus and pore surfaces stain cherry red on application of 3% KOH, and colour is persistent; context tissue stains less intensely or not at all with KOH. HYPHAL SYSTEM dimitic in trama; tramal generative hyphae with clamps, hyaline, thin-walled, 2-3 µm diam.; tramal binding hyphae hyaline, at widest 4.5 µm diam., with wall thickened to 1.2 µm, branches tapering gradually; appearing monomitic in context, with hyphae ribbon-like, sparsely clamped, up to 12 µm diam. with wall to 1 µm thick; conducting hyphae as wide unbranched lengths of generative hyphae staining strongly in phloxine mountant; cortex formed from a compressed layer of hyphae oriented parallel to pileus surface, comprising flattened, ribbon-like generative hyphae to 10 µm diam. (though mostly 3.5-4.5 µm diam.) and thick-walled (to 2 µm) hyphae, 3-7 µm diam. which are sparingly branched and appear to lack clamps. CYSTIDIA absent. BASIDIA clavate, clamped at base, 30-39 x 7-11 µm, 4-sterigmate, with sterigmata approx. 6 µm long. BASIDIOSPORES elongate-ellipsoid, often with a slight depression near apiculus on adaxial surface, hyaline, smooth-walled, IKI-, abundant, in tubes typically nonseptate but rarely to occasionally 1- or 2-septate, on pileus surface at least some are 1-3-septate, rarely tending to disarticulate at septa, 11-18.5 x 4.3-6.2 µm. WOOD ROT white.

New Zealand: Auckland, Bay of Plenty. Australia: Victoria, Tasmania.

SUBSTRATA: Known from dead wood of ?Dacrycarpus daerydioides, Dacrydium cupressinum, and Nothofagus truncata.

Basidiomata stipitata, pileus circularis, umbilicatus, brunneus, leves, pori fascies flavus ad pallide brunneus, pori 1-2 per mm, tubi concolorous, contextus cremus, systema hypharum dimiticum, hyphae generatoriae fibulatae, 2-3 µm latae, hyphae conjuctivae tortuosae, ramosae, crassitunicatae, 2-4.5 µm latae, cystidia nulla, basidia clavatae 30-39 x 7-11 µm, 4 sterigmatibus, basidiosporae cylindrcae ad ellipsoideae, aliquot septatae, hyalinae, tenuitunicatae, 11-18.5 x 4.3-6.2 µm. Cariem album in ligno producit.

ETYMOLOGY: septosporus, referring to septation evident in a minority of basidiospores.
NOTES: This species is separated from all other members of Polyporus by the red reaction of tissue at the pileus and pore surfaces to KOH, and by the septate basidiospores. The red reaction was conspicuous in both fresh and dried material of the holotype, and was less clear though still evident in the darker-coloured dried specimens in PDD 5391. In NZFRI 1759 the coloration with KOH was reddish brown and less distinct than in the holotype.
To our knowledge this species is the first member of the Aphyllophorales to be described with septate basidiospores. Septate spores were readily observed on the pileus surface of the holotype (Fig. 6B,C), where they outnumber nonseptate spores, but they are rare in tubes of that specimen. Septate spores are rare on the pileus surface of PDD 5391 and NZFRI 1759, and were not seen in tubes.
Cunningham (1965) identified PDD 5391 as Tyromyces udus (Jungh.) G.Cunn. (bas. Polyporus udus Jungh.), and mistakenly described hyphae with simple septa; he did not report septate basidiospores. P. udus resembles P. septosporus in pore, basidium, and spore dimensions but, in addition to distinguishing features mentioned above, differs in being distinctly stipitate and having a different hyphal composition (e.g., dimitic context) (Nunez & Ryvarden 1995). P. udus is tropical in distribution and is not known from New Zealand. The identity of two other collections cited by Cunningham (1965) as Tyromyces udus was not determined.
The holotype (K) of Polyporus tasmanicus Massee 1899, non Berk. 1860 is closely similar to P. septosporus in microscopic features, although septate spores were not seen. Massee (1899) reported that his species occurred on the ground, whereas P. septosporus is lignicolous. Cunningham (1950) identified Massee's material as Polyporus pes-caprae (Pers.) Fr. (= Albatrellus pes-caprae (Pers.: Fr.) Pouzar), but the latter differs in features such as the fleshy fruit-body, monomitic hyphal system with inflated hyphae, and mycorrhizal habit.

HOLOTYPUS: New Zealand, Auckland, vic. Bethels Beach, on dead wood in pile of wood at base of Dacrycarpus dacrydioides, J. E. Braggins, 15 Mar 1986 (PDD 66261).