It’s springtime, and the weather is warming up in Te Anau. In the Fiordlands of the South Island the fungi are few and far between now on the Kepler Track. But that doesn’t mean I haven’t been able to find any unique species.
As I make my way down Rainbow Reach towards Shallow Bay and Lake Manapouri, scanning the ground amongst the myrtle beech trees, I spot a few honeycombed Cyttaria gunnii.
Also known as myrtle orange, beech orange, or Maori beech strawberries, this yellow to orange colored fungus is parasitic yet is an edible ascomycete fungus native to both Australia and New Zealand, as well as southern Chile and Argentina.
READ: Fungi in the Fiordlands
Crouched down, I set up the tripod and take some photos and videos of a small insect burrowing inside one of the many concavities. The spores of this particular fungus are black, and the outer ridges darken with age. Insects spread the spores throughout the forest floor.
The spores are also distributed by wind, and once they germinate and penetrate bark tissue, they release chemicals as the fungal hyphae grow. Cells in the tree form, much like a tumor, and Cyttaria gunnii are thus borne. The galls are perennial and keep growing as long as the host branch or stem is alive.
Miles Joseph Barkeley (1 April 1803 – 30 July 1889), an English botanist, cryptogamist, clergyman, and one of the founders of British mycology (over 6000 fungi species are credited to him) and the science of plant pathology, was the first to describe the beech orange in 1848.
Around 38 years later in 1886, the New Zealand fungus, which was assumed to be similar to the Australian one, was described as Cyttaria purdiei.
A molecular study showed that the Australian and New Zealand fungi are, in fact, two distinct species. New Zealand Cyttaria gunnii grows specifically on Nothofagus menziesii, while in southern Victoria and Tasmania in Australia, the species grows on Nothofagus cunninghamii.
The genus has evolved and matches the host genus Nothofagus, and Cyttaria septentrionalis is the closest relative, which parasitizes Nothofagus mooreri (Antarctic beech). This Gondwanan species is estimated to be between 28 and 44 million years ago.
Cyttaria gunnii growth stages
When first finding C. gunnii in Kahurangi National Park near the Flora Hut, I thought that they resemble bunches of grapes. Mostly found in the South Island of New Zealand, the fruit bodies appear in clusters between November and January.
Globular and pear-shaped, they can reach 2.5cm (1 inch) in diameter. C. gunnii are covered by a black-dark brown membrane that bursts, uncovering a network of concavities.
People may experience Trypophobia or fear or disgust from the closely-packed holes (believed to be an evolutionary response to things that are associated with disease or danger).
But aborigines have used the fruit bodies as food. The fungi have a consistency akin to jelly that is reportedly pleasant-tasting. The sweet nectar inside the parts without the holes can be eaten, and, if cooked, the crunchiness and sweetness remain.
The hike was nearly 15 kilometres but was well worth the journey. There’s always something new to discover in the forests of New Zealand. And Cyttaria gunnii is definitely a memorable highlight to hiking the Kepler Track, as well as other Silver beech forests throughout the country.
Dalrymple, H. K. Fungus Hunting in Otago, New Zealand. Coulls, Somerville Wilkie, 1940.