Mycogeography

Cosmopolitan and pan-tropical species

A number of fungi are widespread through human agency (such as unintended dispersal through trade) and there are some examples such fungi in the IMPORTS, EXPORTS AND PUZZLES SECTION. However, there are also many species which were naturally widespread long before humans started transporting fungi. In this section you'll find examples of fungi, found in Australia, which are naturally very widespread. Some of them are cosmopolitan (or virtually so), while others, the pantropical species, are found through most of the tropical areas of the world.

You should remember that while a cosmopolitan species is widespread, that is not the same as saying it turns up everywhere. Many fungi have specific host, substrate or habitat preferences. For example, Podaxis pistillaris is a cosmopolitan species, but in dry habitats.

Cosmopolitan

A good example of widespread distribution is the superficially mushroom-like Schizophyllum commune. This species is found on all continents except Antarctica, growing on wood of all sorts.

The polypore Trametes versicolor is also known from all continents except Antarctica. It is very common in Australia and has been described as probably the commonest wood-rotting polypore in American forests In North America it has been given the common name of Turkey Tail, the banded colours being reminiscent of the bands of colour on the tail feathers of turkeys.

Panellus stypticus is a small, nondescript, creamy to yellow-brown mushroom found growing on dead wood. The stem is very short, and often towards one side of the cap, rather than being central. The morphological evidence (using both macroscopic and microscopic structural features) indicates that this species is found in Australasia, parts of Asia and temperate areas in the northern hemisphere.

The morphological evidence is supported by mating tests that show there is just the one species in all these areas. While it is all the one species, DNA evidence shows that, genetically, there are six distinct geographical groups: eastern North America, western North America+Asia, Europe, southeast Australia, Tasmania, New Zealand. Note that western North America and Asia are given as one group because the western North American examples of the species are genetically closer to the Asian representatives than to those in eastern North America. Why is this so? The Rocky Mountains, which began forming in the Cretaceous period, may have prevented (or at least greatly limited) the gene flow between representatives of the species in western and eastern North America. On the other hand, the land-bridge across the Bering Strait allowed gene flow over a long period, possibly up to as recently as 10,000 years ago. The DNA evidence strongly supports the idea that the species originated in the northern hemisphere, though the evidence cannot determine whether in North America or Eurasia. It seems likely that the species reached ancient Australasia through Asia, possibly through one, or a few, founder events. New Zealand was the last area in Australasia to be colonised by the fungus (well after New Zealand had separated from Australia), quite likely via another founder event.

The Panellus study is an example where geological knowledge, classical morphological fungal taxonomy, mating tests and DNA studies have been brought together to elucidate the history and travels of a species.

As a group, the corticioid fungi (with their flattish, sheet-like fruiting bodies) are found world-wide and many of the individual corticioid species are cosmopolitan. Examples are Botryobasidium subcoronatum , Botryobasidium botryosum , Coniophora olivacea and Dacryobolus sudans . The Shaggy Inkcap (Coprinus comatus ), Coprinus disseminatus , Marasmius oreades and Volvariella speciosa are examples of cosmopolitan, mushroom-producing fungi. Amongst the ascomycetes Leotia lubrica is found in all non-polar continents and Trichoglossum walteri appears to be similarly widespread (except possibly for Africa). The bracket-like Stereum ostrea , with its smooth underside, is a cosmopolitan stereoid species and Polyporus arcularius is another example of a cosmopolitan polypore. Cyathus stercoreus is an example of a Birds Nest Fungus found in most areas of the world, on dung or enriched soil. The so-called Cannonball fungus (Sphaerobolus stellatus ) with its 2mm diameter cups (each with a single "egg") is also found in most areas of the world, on soil or rotting wood.

Within the genus Pycnoporus there are three species, all producing bright orange, bracket-like fruiting bodies. In general terms Pycnoporus cinnabarinus is found throughout the temperate areas of the northern hemisphere, Pycnoporus sanguineus in the tropical and sub-tropical areas and Pycnoporus coccineus in the temperate areas of the southern hemisphere.

Pantropical species

Hexagonia tenuis

A number of fungi are found in all tropical areas of the world - America, Asia, Australasia and Africa. The polypores Earliella scabrosa and Hexagonia tenuis are found throughout the tropical areas of the world, with the Hexagonia being probably the most common polypore in the tropics. In Australia, as well as being common in the tropics, it is also found on the Australian east coast at least as far south as Jervis Bay.

The genus Cookeina produces small, stalked cup-like fruiting bodies with the cups usually no more than about two centimetres in diameter. This is a pantropical genus and Cookeina sulcipes, shown in the Cooke painting at the top of this page, is an example of a species of this genus that is found in northern Australia.

There are also some species which, though predominantly found throughout the tropics, also spread turn up in some temperate areas. Examples are Dacryopinax spathularia , Ganoderma australe and Amauroderma rude . The last of these is found in a number of temperate areas of the southern hemisphere. In fact, the original description (published in 1839) was based on a specimen collected from Tasmania. Leucocoprinus birnbaumii is another example of a tropical/sub-tropical fungus with temperate occurrences. However, in the cooler areas it is confined to glasshouses or indoor pot plants and so has presumably been introduced into temperate areas by humans. In Canberra it appears in most years in some of the glasshouses at the Australian National Botanic Gardens and has also been found in indoor pots in various suburbs.