I think Agrocybe erebis is a good idea, but you should check the details, like spore print and stipe above the ring.
Cortinarius: I' ve seen already heavily serrate gills, but most time this feature isn't mentioned in the descriptions.
I found this concerning descriptions of Cortinarius
(PDF: Cortinarius in Sweden by Karl Soop)
Gills (lamellæ) colour, and edge colour, if different. The colour always pertains to immature individuals. Gill
density and width are reported only if differing from the normal: crowded/narrow in Phlegmacium, and more or
less distant/broad in other subgenera. As a rule, fixation at the stipe is omitted, it being of little diagnostic value:
most Cortinarii have adnate to narrowly free gills when young, that later gradually turn notched to emarginate
during development. Reporting on serrated or crenulated gills is also omitted in most cases, as these characters
vary significantly with age and moisture, as well as among different individuals of a collection.
