Omphalotus olearius, also know as Jack o'Lantern is an orange mushroom that usually grows in dense tufts from the decaying underground roots of olive trees.
initially convex with an inrolled margin, flattening and eventually developing an upturned wavy margin. The colour is bright orange to yellowish-orange. Gills
deeper orange, recurrent narrow and forked. Stem
orange, smooth, tapering and darkening towards the base.
Omphalotus illudens which has a more brighter orange cap.
on the First Nature Web site.