The growth habit is the same as that of Gymnopilus junonius and both have partial veils that, once the cap has opened, remain as rings/skirts of tissue around the stem. In the Armillaria the partial veil has yellow flecks near the outer edge (as in yours and see also photo 3 ofhttps://canberra.naturemapr.org/Community/Sightings/Details/3376814, which concentrates on the ring). Armillaria gives a white spore print, Gymnopilus a rusty brown one. If this were a Gymnopilus, then in your main photo (a very nice view of ring and underside) I'd expect to see a rusty-brownish hue on the gills, because there'd be lots of mature spores on those gills.