The threads on the outer surface of the pileus constitute the cortex or cuticle.
"Studies of American Fungi. Mushrooms, Edible, Poisonous, etc."
George Francis Atkinson
Aethalium with a thick fragile common cortex.
"The Myxomycetes of the Miami Valley, Ohio"
A. P. Morgan
The long narrow, sinuous sporangia closely compacted, entirely grown together and inseparable, covered by a thick common cortex, and seated on a much thickened hypothallus; walls of the sporangia a thin pellucid membrane, coated by a thin layer of white granules of lime.
"The Myxomycetes of the Miami Valley, Ohio"
A. P. Morgan