M3Y4C3E1L1I1U1M3
17 points
MYCELIUM is validvalid
the vegetative portion of a fungus [n MYCELIA] : MYCELIAL [adj], MYCELIAN [adj], MYCELOID [adj]
(Greek) the white threads or filamentous growth from which a mushroom or fungus is developed, also MYCELE [n MYCELIA]