armillaria
Concise Oxford English Dictionary © 2008 Oxford University Press:
armillaria /ˌɑːmɪˈlɛːrɪə/
▶noun a fungus found chiefly in woodland, having mycelia that can grow for a considerable distance. [Genus Armillaria.]
– origin mod. L.: from L. armilla ‘bracelet’ (because of the bracelet-like frill on the fruiting bodies).
'armillaria' also found in these Oxford entries:

