Categories DavidOak roll-rims young and mature Post author By David Post date 7 November 2012 Oak roll rims are mushrooms which often (but not invariably) grow near to oak trees.They have a dull brown cap, and yellower gills, stems and flesh. As they come up they have a domed cap, but as they grow older the rim rises above the centre. ← Birch catkins → Large web lit by the early morning sun