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Mycorrhizal and Mycelial Networks: Scientific Reference

Sat, 28 Mar 2026 00:00:00 +0000

This file supplements the existing conceptual entries (mycelial networks, mycorrhiza, anastomosis, arbuscule, Hartig net) with specific empirical data, quantitative details, researcher attributions, and citations. Where the conceptual files describe what these structures are relationally, this file records what the science actually says – numbers, methods, controversies, and the state of evidence as of early 2026.

¶1. Types of Mycorrhizae

¶1.1 Arbuscular Mycorrhizal (AM) Fungi

Taxonomy. AM fungi belong to the phylum Glomeromycota (reclassified from Zygomycota by Schuessler, Schwarzott & Walker, 2001). Approximately 300-350 described species across ~30 genera, though molecular surveys suggest the true diversity is substantially higher.

Anastomosis

Fri, 06 Mar 2026 00:00:00 +0000

Anastomosis is the fusion of two hyphae to form a continuous connection, converting a branching tree into a true network. Without anastomosis, a mycelium would be a diverging fan of filaments — each hypha branching but never rejoining. With anastomosis, hyphae that encounter each other can fuse their cell walls and merge their cytoplasm, creating loops, cross-connections, and redundant pathways through the network. This is the process that makes mycelium a network rather than a tree, and it is fundamental to everything that mycelial networks do.

Fungal Intelligence

Fri, 06 Mar 2026 00:00:00 +0000

Fungi have no neurons, no brain, and no nervous system. Yet research over the past two decades has documented behaviors in mycelial networks that resemble cognitive processes: path optimization, resource allocation, memory, and habituation. Whether these behaviors constitute “intelligence” depends on one’s definition, but the experimental results themselves are well established.

¶Network optimization

The most famous demonstration involves the slime mold Physarum polycephalum — technically a protist, not a fungus, but one that forms mycelium-like networks and is routinely studied alongside fungi for its network behavior.

Mycelial Networks

Fri, 06 Mar 2026 00:00:00 +0000

The primary body of a fungus is not the mushroom but the mycelium — a branching network of hyphae that grows through soil, wood, leaf litter, or any viable substrate. The mushroom is a fruiting body, a temporary reproductive structure. The organism itself is the network.

¶Scale

Individual mycelial networks can be enormous. The most cited example is Armillaria ostoyae in Oregon’s Blue Mountains, estimated at roughly 965 hectares (2,385 acres) and several thousand years old. Its extent was determined by sampling Armillaria isolates from across the area and testing somatic compatibility — when isolates from different locations fuse and grow together without rejection, they are considered the same genetic individual. DNA fingerprinting (using microsatellite markers) confirmed that the isolates are clonal, supporting the single-individual interpretation. Whether this organism is truly “one individual” in a biologically meaningful sense — or a network of somatically compatible clones that share resources — is debated, but its genetic uniformity across that area is well established.