Sporocarps fasiculate, occasionally solitary, centrally stipitate, tough and fibrous. Cap more or less convex, becoming undulate and edge somewhat incurved when young, smooth to finely fibrillose, grey (1D1, 1E1,) coloured, weakly nigrescent when bruised and eventually becoming black, 10-80mm diameter × 5-20mm high. Stem clavate or cylindrical, narrowing slightly at base and apex, stuffed, smooth, dry, 20-60mm in length x 10-25mm diameter, concolorous with cap and darkening where bruised. Hymenial layer poroid, white 1-2mm deep, bruising pinkish buff (tan), pores angular, 2-3 per mm, drying tan, edge sometimes lacerate. Pore layer extending slightly down the stem and clearly delineated. Smell of dried material weakly of fenugreek, taste slightly acidic. Cap immediately black in KOH, pigment leaching olivaceous black into white absorbent paper. Spore print not obtained.
Hyphal system monomitic. Cap with a differentiated cutis, hyphae 2 µ diameter, with brown plasmatic pigment, hyphal surface covered in small amorphous granular material becoming dark green in KOH and dispersing into medium. Subcutis with inflated gloeoplerous-like hyphae, thin-walled, to 6 µ diameter, clamped. Basidia pleurobasidial, cylindrical to clavate 5-10 × 20-30 µ, 4-spored, with basal clamp. Pores with fringe of slender clavate cystidia-like elements to 80 × 4 µ. Spores very pale tan, thin-walled, not dextrinoid or amyloid, non-cyanophilous, flat-topped tuberculate, length µ=5.3, σ=0.5, width µ=3.0, σ=0.4, Q µ=1.7, σ=0.2 (combined statistics of measurement of 4,11,13 & 20 spores from two fruitbodies of the two collections).
Ectomycorrhizal fungus of wet forests with Nothofagus in New Zealand. Macroscopic appearance of the fungus suggests it might be a Bolete but molecular work places this species in the genus Boletopsis within the Thelephorales. There has been extensive surveying of the Thelephorales by Cunningham (1958 & 1963 ) between 1925 and 1945, and of the Boletaceae by McNabb (1968 ) in the 1960s and by Horak (1971) between 1960 and 1990. None of these observers reported this species. The number of known locations in New Zealand is two, based on both herbarium collections and observational records.
Boletopsis nothofagi has been discovered and described since the last review of the New Zealand
Threat Classification System (Molloy et al 2002); and its classification is currently under consideration by the New Zealand Department of Conservation.
The species is assessed (Following Dahlberg & Mueller 2011) as Critically Endangered under B. Geographic Range for B2 Area of occupancy (NZ 4 km2) along with meeting the subcriteria (a) Severely fragmented, with one population in the Orongorongo Valley in the Rimutaka Forest Park in North Island and the other at West Bay in the Nelson Lakes National park in South Island. There is also concern over the (iii) quality of the habitat, as both known sites are very close to recreational areas where user pressure is affecting the habitat.
The species is also assessed as Critically Endangered under D Very small or restricted population.
D1 number mature individuals, estimated as about 20, based on 2 known individuals, increased by 100% to allow for undetected individuals, and then using a x 5 multiplier to convert to mature individuals. Recorders state that sightings consist of single clump of fruit-bodies at each site.
Preliminary assessment: CR B2ab(iii), D1
Assessed by Tom May, Peter Buchanan, Saphire McMullan Fisher, Patrick Leonard and Jerry Cooper 2015-06-25
Two small populations have been identified, one in the Orongorongo Valley in the Rimutaka Forest Park in North Island and the other at West Bay in the Nelson Lakes National Park in South Island. The two populations are separated by the Cook Strait and there is almost no suitable habitat that might be colonised in the area between the currently known locations.
This taxon is only known from New Zealand. There are no other occurrences of Boletopsis known in the southern hemisphere. The next closest record of a Boletopsis is in Costa Rica.
Ectomycorrhizal in southern beech (Nothofagus) forests and associated with old Nothofagus trees growing in relatively open mature forest with a sparse understorey of Leptospermum scoparium. Ground cover was dominated by lichens in the West Bay site and by mosses in Orongorongo.
The West Bay site lies within the Nelson Lakes National Park and thus receives protection from development. But the site is between a heavily used campsite and a quarry used to extract road fill and not far (200 meters) from a road which has recently seen construction works on a new bridge over the Buller River and a popular walking track. The Orongorongo site is within 5 meters of a well used walking (and cycling?) track. Both populations may be vulnerable to the loss of a single mature tree due to storm, fire or disease.
The identification of the sites in the management plans for both locations would at least protect the species from direct or accidental destruction. Protecting ancient tree specimens and ensuring a succession would at least enhance the chances of the population’s survival.
Better understanding of the biology and ecology of the Bankeraceae would be of great value but would perforce best be conducted in areas where the populations are more secure than these in New Zealand. The USA and Canary Islands (Spain) come to mind as potential sites for such work.
Cunningham G (1963). The Thelephoraceae of Australia and New Zealand. Bulletin 145. Department of Scientific and Industrial Research. New Zealand.
Cunningham, G. (1958). Hydnaceae of New Zealand. Part I. The pileate genera Beenakia, Dentinum, Hericium, Hydnum, Phellodon and Steccherinum. Transactions of the Royal Society of New Zealand, 85, 585-601.
Dahlberg A, Mueller GM, 2011. Applying IUCN red-listing criteria for assessing and reporting on the conservation status of fungal species. Fungal Ecology 4: 147-162.
Horak E. (1971) A contribution towards the Revision of the Agaricales (Fungi) from New Zealand. New Zealand Journal of Botany 9: 403 – 462.
McNabb R. (1968). The Boletaceae of New Zealand. New Zealand Journal of Botany 6 (2), 137 – 176.
Molloy J, et alia, 2002. Classifying species according to threat of extinction. Threatened Species occasional publication 22, Department of Conservation, New Zealand.
NZ Fungi 2 (2015). http://nzfungi.landcareresearch.co.nz/html/mycology.asp