Tuesday, 23 January 2018

Isolated euphorb survives and thrives despite tragic plane crash



Eighty years ago, an Australian National Airways passenger plane, a DC-2, crashed here, on the slopes of Mount Dandenong, in the outskirts of Melbourne. All 18 people on board died when the pilot of the flight overshot Essendon Airport by 32 kilometres on a cloudy afternoon in late October, 1938, a year before the start of World War Two.

The inquiry following the crash led to various air safety improvements including an air traffic control system in Australia that became the model for airports around the world. A memorial was erected at the crash site in 1978.

Near to the memorial is an isolated population of an odd little plant called Beyeria lanceolata. Beyeria is an Australian endemic - all 24 species occur naturally only in Australia - and sometimes (like a few unrelated genera) called Turpentine Bush.


The genus belongs to the plant family Euphorbiaceae, notorious for its single-sex flowers with rather odd and diverse floral apparati, as well as in Africa mostly for the cactus-like Euphorbia species. In recent years a few smaller families have been hived off but Euphorbiaceae remains large (c. 230 genera and 5700 species) and florally odd.

Like other species of Beyeria, the male flowers have obscure petals and consist mostly of a cluster of anthers, in this case poking out of kicked back sepals (the layer outside the petals). The female flowers are a single ovary clasped by green sepals. The leaves are long and narrow.


Beyeria lanceolata grows mostly in East Gippsland, where is is rare but scattered widely, and drifts ever so briefly across the border into southern NSW (where, perversely, the 'type' specimen of the species was collected). West of the township of Sale, though, its only extant population is near this crash site (excluding a likely misidentification from Point Nepean).

The plant was collected from Mount Dandenong in 1949, 11 years after the crash and a few years after the end of the Second World War. At the time of that gathering, Government Botanist Jim Willis noted that this species was 're-located in the Dandenongs' and there were 'many shrubs covering about quarter of an acre'.

Late last year botanist Neville Walsh re-re-located the species in Mount Dandenong - although to be fair it had not really gone missing between 1949 and 2017- estimating its extent at 'about a house block'. Even allowing for house blocks having become generally smaller over the intervening 68 years you'd have to say, as Neville did, that this population has remained remarkably stable.


Still, Neville was there to collect seed, from fruits like this, just in case.

There are other plants with the bulk of their distribution in East Gippsland, and sometimes further northward, but with an isolated occurrence somewhere in the west or centre of Victoria. Examples in the fern and fern ally world include Psilotum nudum, the Fork Fern, in the Grampians; Lindsaea mirophylla the Lacy Wedge-fern in the Dandenongs and nearby; and Tmesipteris ovatum, the Oval Fork-fern from Wilson's Promontory up to the Dandenongs. 

In some cases the clearing of habitat will have caused the disjunction although you'd expect a few older records in between. None of these examples have any historical records connecting the present outliers to their eastern stronghold.

In the case of our Beyeria you might be thinking I introduced the plane crash as a possible vector. Perhaps a seed had become attached to the fuselage? Well I did, but it seems not. The plane was travelling from Adelaide rather than from the east, and there is a pesky August 1914 record - at the start of the World War One - from the same locality.

Images: all from VicFlora, taken by Jeff Jeanes, Neville Walsh and Andre Messina (credits on source page).

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