In the recently published New Zealand inventory of biodiversity volume 3 (Buchanan et al. 2012) contains the following broad summary of our knowledge of mushrooms in New Zealand:
The agarics and boletes include the majority of species that form ectomycorrhizal associations with Kunzea, Leptospermum, and Nothofagus (e.g. species of Amanita, Cortinarius, and Russula …). Levels of endemism are highest among these host-specialised taxa. Of 205 ectomycorrhizal agarics recorded on Nothofagus, about 90% are indigenous and most of these are considered to be endemic …. In total, an estimated 30% of New Zealand agarics are introduced taxa. Cunningham … estimated that 22% of gasteromycetes were endemic; this group also includes several ectomycorrhizal species. Other agarics and boletes grow saprobically on soil, litter, and wood …, contributing to decomposition of organic matter and nutrient cycling, while a few such as Armillaria spp. are pathogenic on plants and some, such as Squamanita squarrulosa, attack other agarics …
I first saw Squamanita squarrulosa in September 1986 growing in a fine moss turf on a bank on the Orongorongo track. The track runs from the Catchool Valley to the Orongorongo Valley through a mosaic of forest types: Nothofagus forest on the drier ridges and mixed podocarp and broadleaf forest in the damp gullies. What caught my eye was a flash of purple amongst the green mossy turf. When I looked closer I saw a small, brown, scaly mushroom with a purplish bulb at the base of its stem.
Back in the lab, I spent hours agonising over it and trying to key it out to a genus. It certainly didn’t fit anything described from New Zealand and the keys kept taking me to Squamanita. Back in the late 80s, Squamanita was an enigmatic genus with a monograph by Bas and no photos that I could find (remember pre-internet). I wrote up the material and sent it to Dr Cornelius Bas in the Netherlands and he agreed that it was a new species of Squamanita, which we called Squamanita squarrulosa. I collected it again from the same spot in 1987 but after that never saw it again.
Then, in 1994 a paper came out of the Pacific North-west of North America (Redhead et al. 1994) naming a new species, Squamanita contortipes, and describing it as the Rosetta Stone that allowed us to understand the rest of the species in the genus. Squamanita contortipes was a parasite of another mushroom! And was growing from the cap of a Gallerina species. All the other species attacked the developing host mushroom and took-over so that usually only the base of the stipe remained recognisable. This explained the weird transition that can be seen Squamanita paradoxa between the base of the stipe and the mushroom at the top – it’s two different species! The host, in this case, is Cystoderma amianthinum. The host was confirmed using molecular evidence by Matheny and Griffith in 2010.
So if Squamanita is a parasite of another fungus what is the New Zealand host? In my field notebook, back in 1986, I had written, “under N.t. [Nothofagus truncata] shaggy caps emerging from purple tuber??” What I meant by a purple tuber is a species of Thaxterogaster. So my first uneducated inclination was I had a parasite agaric growing from a Thaxterogaster fruitbody. However, I quickly moved away from this idea when I decided it was a Squamanita and its species were described as having a tuberous base.
After considering the structure of cuticle of the ‘tuber’ and its colouration I believe that the host is probably Thaxterogaster porphyreum. Squamanita squarrulosa has only been collected once since my original collections in 1986-87. The second photo shows the host ‘tuber’. This collection of mature fruit bodies were found in beech forest in Tongariro National Park in the central North Island in 2005.
Squamanita has been given the English name ‘strangler’, for example Squamanita paradoxa is the powdercap strangler. Since I am suggesting that Thaxterogaster porphyreum or purple pouch is the host for Squamanita squarrulosa then a good English name for it would be the pouch strangler.
Bas C 1965. The genus Squamanita. Persoonia 3: 331-359.
Buchanan PK, Beever RE, McKenzie EHC, Paulus BC, Pennycook SR, Ridley GS, Padamsee M, Cooper JA 2012. Phylum Basidiomycota. In Gordon DP (ed) New Zealand inventory of biodiversity. Volume 3. Kingdoms Bacteria, Protozoa, Chromista, Plantae, Fungi. Pp. 564-584.
Gee H 1995. Mycological mystery tour. Nature 375 (6529, 25 May): 276.
Matheny PB, Griffith GW 2010. Mycoparasitism between Squamanita paradoxa and Cystoderma amianthinum (Cystodermateae, Agaricales). Mycoscience 51: 456-461.
Redhead SA, Ammirati JF, Walker GR, Norvell LL, Puccio MB 1994. Squamanita contortipes, the Rosetta Stone of a mycoparasitic agaric genus. Canadian Journal of Botany 72: 1812-1824.