Aseroe rubra. Photo: B. Baldock.

A diminutive, but spectacular fungus has emerged from the leaf and bark litter in the Australian Forest section of the Adelaide Botanic Gardens. It is Aseroe rubra Labill., with 6 to 8 bright red arms spreading like forked spokes of a wheel. It has several common names that aptly describe an observer’s first response when they encounter it: sea anemone fungus, starfish fungus or …stinkhorn fungus.

Usually several, inconspicuous, partly buried “eggs” about 30 mm across are first to emerge. Each then splits and spreads its red arms (see time-lapse video at this link) to expose a central, slimy, stinking mass of spores. Flies find this irresistible, and, walking over the surface, pick up and disperse spores on their bodies. Perhaps the colour, shape and smell remind them of an open anus of a larger animal, complete with remnant droppings and worth a visit! Disgusting? Well, evidently successful for the continued existence of the fungus.

Aseroe rubra “eggs” and expanded fungus. Photo: B. Baldock.

It was originally described by the French botanist Jacques-Julien Houton de Labillardière from Tasmania, when the French were racing with Flinders to explore Australia in the 1800s. We now know it can be found across Australia and New Zealand, and has also popped up in Europe and North America.

If you are quick, you can see them growing in the mulch on the edge of the paths to the west of the Bicentennial Conservatory, while the favourable conditions last.

Hovea purpurea, State Herbarium of South Australia specimen AD96413149

A Remarkable occurrence

The Plant of the Month for May, Hovea purpurea, alpine hovea or rusty pods (formerly known as H. longifolia & H. beckleri), is an attractive violet-flowered shrubby pea with a disjunct outlying occurrence in the State that is truly remarkable.

Alpine hovea has its principal occurrences in eastern NSW and north-eastern Victoria (see AVH map) but re-appears over 1000 km to west on a few of the taller peaks in the Southern Flinders Ranges, which provide a refuge of cooler and moister conditions. The largest population here occurs on the rocky slopes of Mt Remarkable in DEWNR‘s Park of the Month for May 2016: Mt Remarkable National Park.

As well as Mt Remarkable and its northerly extension, the species occurs on the upper slopes of Mt Brown, The Dutchman’s Stern and Mt Aleck (in the Elder Range). There is also a Tate herbarium collection from the Gladstone area (probably from the late 19th century) and a single collection made in 1960 from St Mary’s Peak on the rim of Wilpena Pound. It would be good to have confirmation for these locations on the southern and northern extremes of its SA range, but the absence of recent records for such a striking plant suggests that it is no longer extant there.

Hovea purpurea specimen, detail with flowers

Being restricted to such a small zone on only the highest peaks of the southern Flinders Ranges, alpine hovea in SA is likely to be highly susceptible to climate change: there is no higher zone that it can shift up to as conditions become progressively warmer and drier.

The AD herbarium specimen shown here illustrates the species’ erect habit and distinctive leathery leaves that are smooth above and rusty-velvet below. It was collected by H.M. Cooper on Mt Remarkable in 1963 and still retains much of the original flower colour 53 years on.

H.M. Cooper (1886-1970) worked as an anthropologist with the South Australian Museum and, like many people of his time, had wide-ranging interests in natural history. Cooper contributed thousands of items, mainly aboriginal stone artefacts to the Museum’s collection, but also made important collections of fish, insects, land snails and plants. The latter collections are represented by over 3680 records in the State Herbarium database.

Hovea purpurea is listed as a Rare species in SA under Schedule 9 of the National Parks and Wildlife Act. Although its range is localised, alpine hovea is a prominent plant on the upper slopes of Mt Remarkable and hard to overlook when it is flowering in early spring.

Hovea purpurea, flowers & immature fruit, Mt Remarkable National Park. Photo: SA Seed Conservation Centre.