#35 Cordyceps gunnii

The Hunter Valley has received light showers of rain recently (as has many other parts of eastern Australia), hence the time is right for fungi.

Cordyceps gunnii (Dark Vegetable Caterpillar) is an intriguing fungus. Cordyceps are parasitic fungi, but rather than choose a plant as a host like many other parasitic fungi, they attack insect larvae.

The mycelium (underground mass of microscopic fungi filaments called hyphae) of cordyceps gunnii invades a moth larva, feeding on it and eventually replacing the host tissue. An elongated fruiting body is then sent to the surface to distribute spores to aid in the spreading of the fungus.

Cordyceps gunnii fruiting bodies
Werekata National Park, Cessnock, NSW

The black club-like or finger-like Cordyceps gunnii fungus fruit-bodies usually appear under mature wattles. The habitat of the examples featured here was Eucalypt, Leptospermum and Acacia woodland. Fruit-bodies have a height of up to 120mm above the ground, are dark olive-green to black in colour, are cylindrical or flattened with a blunt end. The smooth surface is covered in minute dots (ostioles), from which white spores emerge.

The head merges smoothly into a stem - this is an identifying feature, separating it from other dark club-like fungi. The white to pale yellow underground stem can reach 400mm, depending on the depth of the moth larva it has parasitised.

Cordyceps gunnii grows singly or in groups, and is known to be common. I found a colony of more than 20 fruiting bodies after rain.

A copious amount of white spores surrounds
this Cordyceps fruit-body

Notice the smooth transition from head to stalk.
My hand gives a size comparison.

The tiny 'dots' on the head are openings for spores
to emerge from the mature fruiting body

This Cordyceps fruit-body is coated in white spores

A flattened, rather than the usual cylindrical fruit-body

If a caterpillar larva is especially rich in nutrients
two clubs of the Dark Vegetable Caterpillar may emerge

I managed to extract the full stem of this Cordyceps

My sightings of Cordyceps gunnii

[This will be updated with new sightings]

Werekata NP, Cessnock, NSW - Eucalypt, Leptospermum and Acacia woodland - Jul

New England NP, NSW - Native forest - May.

#34 Auricularia cornea

Many newly emerged fungi fruiting bodies look vastly different to the mature fungus, making identification difficult. In this blog I will try to illustrate, in photos, the different stages of the life cycle.

Auricularia cornea (Jelly Ear Fungus),belongs to the jelly group, which are generally gelatinous in texture and appearance, having a high water content.

The upper sterile surface of Auricularia cornea is covered in a dense silky coat of minute pale grey hairs. The lower fertile surface is smooth and hairless. The spores are white, and I have actually been successful obtaining a spore print (not an easy task for jelly fungi).

The shape of a mature fungus is usually convex. When crowding occurs, the fungi are contorted into irregular shapes, often with wrinkled surfaces. The consistency of the flesh is tough (doesn't break with rough treatment, and is difficult to tear with force), wobbly in a gelatinous manner - rubber-like. Colour is reddish brown, and translucent, drying to nearly black.

Auricularia cornea has the remarkable ability to rehydrate many months after it has dried out. I have witnessed a colony of this fungus rehydrate several times after rain throughout a 1 year period. I presume the fruiting bodies are resistant to insect and invertebrate attack when in a dessicated state, but I am unaware if the rehydrated fungus produces a second or third flush of spores.

Substrate is dead wood in tropical to subtropical forests, but I have observed them on dying exotic trees in suburbia.

A freshly rehydrated colony of Auricularia cornea

Tiny new velvety fruiting bodies of Jelly Ear Fungus.
The right-hand top corner of the image is covered
by a mature specimen.

A close-up of new fruiting bodies about 1cm in diameter.
Notice more new fungi pushing up the bark of the tree.

Smooth maturing specimens.
Notice the hollow surface white with spores.

Without crowding, the fungi are not wrinkled.
Minutely hairy upper surface, smooth undersurface

Some will take on strange shapes,
but still generally convex.
Note the tiny new fruiting bodies above and below.

The velvety hairy upper surface joined to wood.

Fruiting bodies can reach in excess of 100mm.

Crinkled, translucent, crowded fruiting bodies.

Auricularia cornea fruiting bodies dry to an almost black
under surface, but will return to cinnamon-brown
when rehydrated by rain.

My sightings of Auricularia cornea

[This will be updated with more sightings]

Singleton, Hunter Valley, NSW - Dying exotic tree, residential garden, all year

Barrington Tops National Park, NSW - Dead wood, rainforest

Hunter Region Botanic Gardens, Heatherbrae, HV - Dead wood, woodland

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Edit - an interesting experiment: Following a heavy downpour 14th July 2010, I collected some rehydrated fruit bodies of Auricularia cornea from the tree in my front yard and prepared them for spore prints. I successfully collected excellent spore prints, therefore it is interesting to note that rehydrated fungi (this species, at least), do in fact produce new flushes of spores.