1) Hypha 
A macroscopic, typically rope-like strand of compacted tissue formed by certain higher fungi. Rhizomorphs often are enduring structures that can remain dormant under adverse conditions. 
(from the article `Armillaria`) Armillaria grow from a single fertilized white spore and spread vegetatively through hyphae, threadlike filaments of cells that aggregate to form ... Various other tissues are also produced by the interweaving of the assimilative hyphae of some fungi. Stromata (singular stroma) are cushionlike ... ...m...
An aggregation of hyphae resembling a root and having a well defined apical meristem capable of transporting nutrients and spreading infection over considerable distances; often differentiated into a rind of small dark cells surrounding a core of elongate colourless cells.
A specialized form of mycelium produced by certain fungi (e.g. Armillaria spp.) consisting of several strands of hyphae twisted together so as to be rootlike, and covered with a protective sheath.
[n] - a dense mass of hyphae forming a rootlike structure characteristic of many fungi
noun a dense mass of hyphae forming a rootlike structure characteristic of many fungi
A root-like branched strand of fungus.