Identify Red Starfish Fungus (Aseroe rubra) - Plant AI mycology guides
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Red Starfish Fungus

Scientific Name: Aseroe rubra

The Red Starfish Fungus, also known as the Anemone Stinkhorn or Starfish Fungus, is a bizarre, fascinating, and inedible wild fungus native to Australia, Tasmania, and widely introduced worldwide. Thriving in damp garden mulch, leaf litter, and forest soils, it is named for its striking resemblance to a sea anemone or a bright red starfish. Sprouting from a buried white egg, it features a hollow white-to-pink stalk topped by 6 to 10 bright crimson-red branched arms radiating outwards around a highly foul-smelling, dark brown spore slime.

🌍 Environment Damp Gardens & Mulch Beds
💧 Humidity High Humidity (75-85%)
🪵 Substrate / Host Decomposing Woodchips / Leaf Litter
📏 Size 5cm - 10cm
🍄 Category Inedible
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How to Identify

A bright red starfish-shaped cap with branched arms radiating from a central disk covered in dark-brown, foul-smelling slime.

  • Starfish-shaped Arms: Cap features 6 to 10 bright carmine-red arms that are deeply divided or branched at the tips.
  • Foul-smelling Gleba: The central disk is covered in a sticky, olive-brown-to-dark-brown slime that smells strongly of rotting meat.
  • Hollow Stalk & Egg Base: The stalk is hollow, cylindrical, white at the base turning pink-red at the top, emerging from a white egg-like sac.
🚫 Inedible & Odor Warning: Not toxic, but completely inedible due to its tough, spongy texture and extremely foul, nauseating stench. The smell is a natural mechanism to attract flies for spore dispersal.

Detailed Mycology Profile & Safety Guide

Click on any dimension to expand detailed field guides, substrate requirements, and safety warnings.

Grows as a saprophyte on decomposing organic matter, bark mulch, garden woodchips, leaf litter, and grassy pastures. Common in Australian rainforests and damp suburban gardens.
Requires warm, humid summer and early autumn conditions (18-26°C) and high moisture. Sprouts rapidly after heavy rains.
Tolerates direct sun in mulched gardens, but thrives best in partial shade where soil moisture is retained.
No cap or gills. Spores are produced in the dark olive-brown, sticky, foul-smelling gleba concentrated in the central cup-like disk.
Spore print is not traditionally collected. Propagates via flies, beetles, and gnats attracted to the carrion odor, which carry spores on their bodies.
Flesh is spongy, thin, pinkish-red, fragile. Stalk is hollow, white-to-pink, emerging from a dirty white egg-like base volva. Lacks a ring.
Do not harvest. Foragers and gardeners usually leave them in place or remove them to prevent their strong, unpleasant rotting odor in suburban yards.
Inedible. There is no culinary value due to its spongy texture and persistent, repulsive fecal-carrion odor.
Contains high levels of nitrogenous compounds, minerals, and complex odor chemicals (dimethyl disulfide) that mimic decaying animal tissue.
CRITICAL WARNING: Extremely unique! Easily distinguished from other stinkhorns like **Octopus Stinkhorn** (Clathrus archeri) which has **slender octopus-like arms growing vertically**, whereas Red Starfish Fungus has a **horizontal starfish-like flat disk** atop a distinct stalk.
If this fungus sprouts in your garden mulch, do not panic. It is a beneficial wood-decomposer that helps break down mulch into fertile soil. The smell and mushroom will dry up and disappear in a few days.
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Foul Odor & Fly Swarms

Symptoms: The mushroom is covered in dozens of flies and emits an intense smell of rotting meat.

Action: Action: This is natural. The foul odor is how the stinkhorn attracts insects to carry its spores. If the smell is too close to your home, dig up the mulch slightly and discard the white egg base.

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Shriveling & Browning

Symptoms: The bright red starfish arms turn pale, dry, brown, and shrivel flat against the mulch.

Action: Action: This is natural decay. The fruiting body has completed its spore release and is decomposing back into the mulch. No action is required.

Frequently Asked Questions

Why does it look like a starfish?

Its sea-anemone or starfish shape, combined with the bright red color, is an evolutionary design to mimic carrion or decaying flesh, attracting insects to help disperse its spores.

Is the Red Starfish Fungus poisonous?

No, it is not known to be chemically toxic. However, it is considered completely inedible due to its tough, spongy structure, lack of nutritional value, and repulsive odor.

How long does the mushroom last?

The entire lifespan is very short. It emerges from its egg-like base, fully expands into a red starfish shape, releases its spores, and shrivels up all within 24 to 48 hours.

How do you prevent it from growing in garden mulch?

Since it grows on decaying wood, you can reduce its occurrence by turning your mulch regularly to dry it out, or by replacing woodchip mulch with gravel or composted leaves in shaded areas.

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