Rhodocollybia 'furry, red-brown'

The fruitbody is a mushroom with a cap atop a central stem. The cap may be up to 30 millimetres wide and is shallowly convex to almost flat. It is reddish-brown, dry and has whiteish, radially arranged fibrils that lie flat on the cap, except in the outer third or half, where they stand out and make the cap markedly hairy. The gills are white and have slightly ragged edges. The stem has a dense covering of whiteish bristles and may be up to 65 millimetres long and 6 millimetres in diameter.

There is no evidence of any veil.

The mushrooms appear on rotten wood.

Look-alikes

G. Gates and D. Ratkowsky (A Field Guide to Tasmanian Fungi. 2nd edn. Tasmanian

Field Naturalists Club, 2016) include a species they call Gymnopus 'pink furry', with a cap up to 15 millimetres in diameter and a stem up to 15 millimetres long. J. Hubregtse (Fungi in Australia, Part 3, available at http://www.fncv.org.au/wp-content/uploads/publications/fungi_in_australia/fia-3-basidio-agarico-I.pdf) includes the same species and notes the gills as "finely serrate". Both works include photos and (ignoring size) their Gymnopus looks very much like Rhodocollybia 'furry, red-brown'. Either, we have two macroscopically similar species or we have one species with some argument as to which genus it belongs to. Given that the two genera have some similarities, that would not be surprising.    

So, why use Rhodocollybia rather than Gymnopus?  The brief macroscopic description given above for the Rhodocollybia is based on an examination of the two specimens associated with the sighting https://canberra.naturemapr.org/sightings/4383298. The spores are colourless when placed in water and then viewed under the microscope. Some, though not all, of these colourless spores turn reddish in Melze'rs reagent (a yellowish iodine solution). Furthermore, the whole spore doesn't become reddish, the colour being truncated a little before the apiculus, by which the spore is initially attached to a basidium (the spore-producing organ). These facts point to Rhodocollybia, since Gymnopus does not show a reaction in Melzer's reagent. Furthermore, Jerry Cooper (see his key to New Zealand species in https://www.funnz.org.nz/sites/default/files/MycNotes31-GymnopusAndAllies_1.pdf ) uses the truncate, reddish (technically, dextrinoid) reaction and lacerate gill edges to help distinguish Rhodocollybia from Gymnopus.