🍄 Mycelium Network Growth

Simulate fungal mycelium growth as a branching network. Hyphal tips extend toward nutrient gradients, anastomose (fuse), and transport resources through the network.

Life ScienceInteractive
Click canvas to add nutrient patch · P pause · R reset

How it Works

This simulation models fungal mycelium as a collection of growing hyphal tips on a 2D substrate. Each tip has a direction angle and extends at a fixed speed, drawing a segment. At each step, tips may branch (probabilistically) or be deflected toward nearby nutrient patches.

Anastomosis (hyphal fusion) is simulated: when two tips come within a threshold distance, they fuse, incrementing the anastomosis counter and preventing further growth from both — mimicking the real biological process that creates loops in the network and enables resource redistribution.

Direction update: θ_new = θ + α·∇C + η·ξ
where ∇C = gradient toward nearest nutrient source
α = nutrient attraction strength, η = noise amplitude, ξ ∈ [-1,1]
Branch prob: P_branch = b · dt (per tip per frame)

Frequently Asked Questions

What is mycelium?

Mycelium is the vegetative part of a fungus, consisting of a network of fine white filaments called hyphae. It grows through soil, wood, or other substrates, absorbing nutrients.

How do hyphae grow?

Hyphae grow by extending their tips (apices) outward. Cell wall material is added at the tip, driven by vesicle fusion and turgor pressure, allowing the hypha to penetrate and explore new substrate.

What is anastomosis in fungi?

Anastomosis is the fusion of two hyphae to form a connected network. This allows resource sharing and communication across the mycelium, making the network more resilient and efficient.

How does nutrient gradient guide mycelium growth?

Hyphae exhibit chemotropism: they sense chemical gradients (e.g., sugars, nitrogen compounds) and bias their growth direction toward higher nutrient concentrations, optimizing resource acquisition.

What is the fractal dimension of mycelium?

Mycelial networks often have fractal dimensions between 1.5 and 1.9, meaning they efficiently fill space while remaining less than fully 2D. This geometry maximizes surface area for nutrient absorption.

How fast does mycelium grow?

Growth rates vary enormously by species and conditions. Some species extend tips at 1–10 micrometers per minute. Under optimal conditions, a colony can expand several centimeters per day.

Can mycelium conduct electrical signals?

Yes, research has shown that hyphae can transmit electrical action potentials along the network, analogous to nerve impulses. These signals may coordinate growth responses across the colony.

What is the role of mycelium in ecosystems?

Mycelium decomposes organic matter, cycles nutrients, forms mycorrhizal associations with plant roots, and creates the 'Wood Wide Web' that connects and supports forest ecosystems.

What mathematical models describe mycelium growth?

Reaction-diffusion models, branching random walks, and lattice-based tip-growth models are used. The Edelstein model tracks hyphal tip density and substrate as coupled PDEs.

How does temperature affect mycelium growth?

Mycelium growth typically follows a bell-shaped temperature response. Each species has an optimal range (often 20–30°C); growth slows below and above this range, ceasing at extremes.

About this simulation

Six hyphal tips start at the centre and each frame bends its heading toward the nearest green nutrient patch, adds a small random walk, and occasionally spawns a branch — the same chemotropic-plus-noise rule real fungi use to explore soil. When two tips wander within 8 pixels of each other they anastomose: they fuse, stop growing, and the counter ticks up, mirroring how real mycelial networks form resilient loops instead of a simple tree.

🔬 What it shows

A branching green filament network expanding outward from a central point, curving toward glowing nutrient patches, fusing where strands cross, and slowly depleting the food sources it consumes along the way.

🎮 How to use

Adjust Growth Speed, Branch Probability, Nutrient Attraction and Max Tips with the sliders, click anywhere on the canvas to drop a fresh nutrient patch, or press P/R to pause/reset.

💡 Did you know?

Real mycelial networks form the "Wood Wide Web" — underground fungal highways that link tree roots across a forest, letting trees share nutrients and even send chemical warning signals to neighbours.

Frequently asked questions

What happens when I click on the canvas?

Clicking adds a new nutrient patch of amount 120 and radius 40 at that point, which immediately starts attracting nearby hyphal tips via the nutrientDir() gradient calculation.

Why do two tips sometimes disappear and merge into one?

That is anastomosis: whenever two tips come within 8 pixels of each other, one is removed and the anastomosis counter increments, simulating real hyphal fusion that creates network loops.

What does the Nutrient Attraction slider actually control?

It scales how strongly a tip's heading is pulled toward the angle returned by nutrientDir(), which sums weighted direction vectors from every unconsumed nutrient patch in range.

Why do nutrient patches fade over time?

Each patch has a finite amount that depletes by up to 0.3 units whenever a hyphal tip passes within its radius, so heavily visited patches dim and eventually stop attracting growth.

Why does branching stop even with a high Branch Probability?

New tips only spawn while the combined tip count stays under the Max Tips setting, so once that ceiling is reached the network keeps extending existing tips without adding more branches.