Resinicium?

[Steve]

This minutely hydnoid (odontoid) crust was on debarked pine at Longshaw, Derbyshire. Although it produced a good spore deposit, I was unable to find any basidia even under oil immersion. The microscopy was done on the dried specimen, which was hard and resinous, very difficult to section, and when hydrated with KOH or water, produced a rather messy soup. Features akin to Resinicium as described in Fungi of Switzerland and Corticiacaea of Northern Europe are the waxy texture, the spores (non-amyloid, typically 6 x 2.5, one side sometimes straight), clamped hyphae and balloon-shaped cystidia. One of those in the image appears to have a halo. The fungus was infected by a dark hyphomycete. Resinicium bicolor would fit the habitat of bare pine wood, but should have star-shaped cystidia as well. R. pinicola might fit better but for the shortness of the teeth (though the fungus might have been grazed).
Steve

Field photo

Stereo microscope image x45

Section x 100 in Congo Red

Section of "tooth" x 600 in Congo Red

Spores x 600 in water

Cystidia above, clamped hyphae below, x1000 in Congo Red

[Andy Simpson]

Hi Steve,
Looking at your images and measurements, Resinicium furfuraceum looks a good fit, with halocystidia, lack of astrocystidia, spore size and clamps. Basidia for R. furfuraceum much smaller than R. bicolor, at 10-12, according to Fungi Europaei 12, so may not be obvious.
Andy

[Steve]

Hi Andy.
Many thanks for that. R, furfuraceum is described on Pinus in half of the 8 FRDBI records - so I think you are right if we see this one as grandinioid (granular) rather than odontioid-hydnoid (small teeth).
Cheers,
Steve