my·ce·li·um 
(mī-sēlē-əm)
(mī-sēlē-əm)n. pl. my·ce·li·a (-lē-ə)
1. The vegetative part of a fungus, consisting of a mass of branching, threadlike hyphae.
2. A similar mass of fibers formed by certain bacteria.
[New Latin : MYC(O)- + Greek hēlos, wart.]
my·celi·al (-lē-əl) adj.