Tuesday, 11 November 2014

Better to have foraged for Fairy Lanterns and failed…


I gather the thrill of shopping is as much about the planning, the anticipation and the hunt, as it is about the purchase. Still I suspect without an occasional purchase it might become a little anticlimactic.

Plant foraging is a bit similar, particularly if you are looking for native ground orchids. On Melbourne Cup weekend last year, Lynda and I took up the ultimate botanical challenge, a native under-the-ground plant closely related to orchids.

We were in the Otway Range, rummaging around one of only six known localities for Fairy Lanterns, Thismia rodwayi, in Victoria. And we were unsuccessful. Not a tentacle to be seen. Perhaps we were in the wrong place at the wrong time. Or the right place at the wrong time. And so on. It’s not easy to find something that lives its entire life underneath the leaf litter.

If we had found it, it would have looked like this (each lantern-like flower is about 3 cm long):


We seem to have only one species of Thismia in Victoria, but when a plant is this hard to locate and study, who knows? Ten years ago a new species was discovered in Morton National Park, near Bundanoon in New South Wales. It was only the second report of Thismia from New South Wales.

Local naturalist Pat Jordan was part of a community fungal survey, Fungimap, in her local National Park. She thought the flower was a fungus and sent it our fungal expert here in Royal Botanic Gardens Melbourne, Dr Tom May. Recognising it as a Thismia, Tom showed it to visiting botanist Kevin Thiele, based in East Gippsland where the genus is relatively well known. He declared it a new species.

Thismia grows almost entirely underground and produces no leaves. It bears a single red to orange tubular flower, with a mitre-like cap and tentacles just emerging into the leaf litter. The whole plant is about 3 cm long. And only a few people have ever seen them in the field in Australia.

There are 30 known species of Fairy Lantern, mostly in South-east Asia and South America. Before this species was discovered there were only two known from Australia – one in Cape York, the other scattered around southern Australia.

Fairy Lanterns are closely related to orchids. The huge orchid family, Orchidaceae, includes over 20,000 species, of which only two grow underground. They both belong to the genus Rhizanthella, first discovered in 1928 near Corrigin in south-western Western Australia, and so far unknown outside Australia.

Fairy Lanterns and these orchids rely on fungi growing on the roots to get all their food and nutrients – they are mostly underground and don’t have any green parts so they can’t photosynthesise their own sugars and energy.

How are they discovered? Usually by accident. But also after very careful and intensive searching of likely areas.

The species are distinguished from one another mostly on the type of tentacles on the mitre-like cap. The Bundanoon species has been named clavarioides due to the resemblance of these tentacles to the ‘coral fungus’ Clavaria. When Pat Jordan first saw the tentacles of these flowers she thought they were a coral fungus.

The complete distribution of such underground plants is not the only mysterious thing about them. So too is their method of pollination. The flowers of fairy lanterns and underground orchids appear to rely on tiny flies, ants and termites, or other insects that flit about in the litter layer. Yet many ants—the most common visitors to the Western Australian underground orchid—secrete a potent antibiotic called metapleurin that should kill pollen. How the orchid overcomes this, we don’t know.

In the case of fairy lanterns the flowers are designed like yabby traps. Kevin Thiele postulates that insects can escape the trap but only after squeezing past a gland (that may secret glue) and the pollen sacs. The fruit of all these underground plants is probably dispersed by small marsupials searching for underground ‘truffle-like’ fungi such as truffles, but again we can’t be sure.

So plenty to discover about the Fairy Lanterns, as well as where they live. On balance I think its best I didn’t find one on my first search. Like travel, rather than shopping perhaps, it’s good to miss a few things so that you still have things to plan, anticipate and hunt.

And I'm well used to this kind of unfulfilled potential from above-ground orchid hunting. I saw a few orchids in flower over the Melbourne Cup weekend, but not great display. Although at least with above-ground orchids you often find a leaf, or a spent flower. These two are from Anglesea, on the return trip from the Otway Range. They will be readily recognisable to those with the bug.


Images: The Thismia picture was taken by Neville Walsh, and is from the Otway Range. Note also that some of the information in this post is taken from a story I wrote for Nature Australia magazine in 2004 (not available on-line).

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