September 1^st is Wattle Day, so the State Herbarium of South Australia has chosen golden wattle, Acacia pycnantha Benth., as the plant of the month for Belair National Park, DEWNR‘s Park of the Month (the history of the park is described in this chapter in Valleys of stone)

Acacia pycnantha, inland form. Photo: M.C. O’Leary.

Acacia pycnantha is a variable species that naturally occurs from southern New South Wales west to the Flinders Ranges and Eyre Peninsula, and is common in Belair National Park. Inland plants have a tendency to form slender small trees with narrow phyllodes and pale flowers, while those in wetter coastal habitats grow into larger trees with broader phyllodes and deep golden flowers.

Acacia pycnantha is widely cultivated and has become a weed in Australia and many countries around the world. In the 1980’s Trichilogaster signiventris wasp galls with young were sent to South Africa from Adelaide Botanic Gardens as a biocontrol. This introduction was a success and seed production was greatly reduced — the wasps lay eggs into the developing flower heads which produce galls that prevent seed formation.

Natural distribution of Acacia pycnantha.

In 2011 & 2012 African researchers visited the State Herbarium and conducted fieldwork with staff, revisiting the original collection site and genetically sampling populations across the range of A. pycnantha in Australia. The success of the wasps from South Australia was found to be due to the similarity with the weedy plants in South Africa, where other introductions had failed (see Annals of Botany 111: 895-904).

Acacia pycnantha (left) and A. provincialis (right). Fanny de Mole, Wildflowers of South Australia, 1861. Image: National Library of Australia.

The gum of Acacia pycnantha was an important summer food for the indigenous Nations where the plant occurred. This was noticed by the European settlers around Adelaide and the export of gum became an early industry. Fanny de Mole illustrated the species as one of the gum wattles in her 1861 book Wildflowers of South Australia.

Another important industry of the time was wattle bark for tanning, with Acacia pycnantha bark considered to be one of the richest tanning barks in the world. This resulted in extensive clearance of this common species. Later plantings of the species were conducted with limited success, and eventually Australia’s industry was out-competed by South Africa. Today Australia imports most of its tannin requirement, over $6 million per annum.

Australia Post stamp issued 9 Sep. 1959, design by Margaret Stone.

In 1988 Acacia pycnantha was officially proclaimed the Australian floral emblem and in 1992 the first of September was proclaimed as Wattle Day. However the desire for an Australian floral emblem and day of celebration had a long history. In 1889 the Adelaide branch of the Australian Native’s Association (exclusively male) suggested the formation of a Wattle Blossom League. In 1891 a Wattle Blossom Banner was publically displayed for the first time in Adelaide in connection with Foundation Day ceremonies. 1899 saw the formation of a Wattle Club in Victoria with outings on September first. In 1910 the South Australian and Victorian branches of the Wattle Day League were established, and the first Wattle Day was celebrated in Sydney, Melbourne and Adelaide on September first. In 1912 the Adelaide branch of the Wattle Day League called for the golden wattle to be the national flower and emblem of Australia. In 1915 the first memorial for the First World War in Australia was erected by the Wattle Day League in the southwest parklands at “Wattle Grove”. In 1919, Henry John (Harry) Butler dropped a golden wattle plant by parachute from his plane into Wattle Grove (presumably the first planting by plane). The League and Wattle Day gradually petered out after World War Two, in part being replaced by Arbour Day.

Contributed by State Herbarium botanist Martin O’Leary.

Drosera praefolia, buds. Photo: P.J. Lang.

Precocious little early bloomer

The plant of the month for August 2016 is Drosera praefolia, a rare South Australian endemic sundew with the peculiar trait of flowering before its leaves appear.

It is one of an amazing six sundew species found in Onkaparinga River National Park, which is the DEWNR Park of the Month for July. The other sundew species recorded there are the pink-flowered Drosera auriculata (tall sundew), the tiny D. glanduligera (scarlet sundew), D. hookeri (pale sundew), D. macrantha subsp. planchonii (climbing sundew) and D. whittakeri (scented sundew). This is a good time of year to see most of the species. Try the easy 5 km Sundews Ridge Hike or the steeper, more challenging 6 km Sundews River Hike.

Sundews (Drosera spp.) are insectivorous plants bearing stalked glands which produce a sticky mucilaginous material to attract and trap insects. These glandular hairs are responsive to pressure when an insect gets caught and bend in towards it to make further contact. Enzymes are secreted to digest the prey and release nutrients that the plant can absorb. The new treatment of the Flora of South Australia (5th edition) covering all the State’s Drosera species is available here as a pdf file (Conran & Marchant 2011; 3MB PDF).

Drosera praefolia, flowers. Onkaparinga River National Park. Photos: P.J. Lang .

Drosera praefolia resembles the more widespread and common Drosera whittakeri: both species are geophytes with their leaves arranged in a rosette that regrows each year from an underground tuber. Having this underground energy store from the previous season’s growth makes it possible for D. praefolia to flower much earlier and in advance of leaf production. Drosera praefolia flowers April to May and often produces mature seed before its leaves appear, in contrast to D. whittakeri which flowers July to October from fully-formed leaf rosettes.

Drosera praefolia, two typical rosettes. Photo: J.G. Conran.

Evolution of precocious flowering in D. praefolia may have been driven by natural selection to “beat the rush” and catch earlier pollinators in the face of strong competition during winter and spring when conditions are optimal for plant growth and subsequent flowering. Precocious flowering is also a feature of a number of late-summer and autumn flowering lilies, for example Calostemma, as featured in an earlier blog, and Crinum.

Pioneering South Australian botanist and entomologist Johann Gottlieb Otto Tepper described Drosera praefolia in 1892 (in German) drawing on collections and observations he made at Clarendon in the Onkaparinga River Valley ten years earlier while stationed there as a teacher.

Drosera whittakeri. Photo: L.M.B. Heard.

However, D. praefolia was either disregarded or treated merely as an early-flowering variety of D. whittakeri for over a hundred years, until it was reinstated as a species by Bates (1991) (230KB PDF). This is despite its many other differences from D. whittakeri, including smaller flower size, a white (rather than orange) tuber, and leaves with shorter, non-ribbed petioles. For a full account, see the review of the Drosera whittakeri group by Lowrie & Conran (2008) (2.7MB PDF).

Contributed by State Herbarium botanist Peter J. Lang.

Sargassum decurrens. Photo: B. Baldock.

Adelaide shores have recently been battered by high winds and waves, and we generally concentrate on the damage they cause to landscape and property. But storms may also wash in the unusual and unexpected.

A volunteer from North Haven, who works in the State Herbarium of South Australia‘s Phycology Unit, brought in a brown alga, Sargassum decurrens (R.Br. ex Turner) C.Agardh, cast up by the rough weather. Sub-tropical, generally found in Western Australia, Northern Territory and Queensland, this species has only occasionally been found growing in northern Spencer Gulf of South Australia at depths of 6 to 10 m. It’s probably a relict from a time when local seas were warmer, got trapped in the larger of our gulfs when the climate changed and now survives precariously, together with several other sub-tropical species, in areas of high summer temperatures — other relict species include the brown alga Hormophysa triquetra (C.Agardh) Kützing and the red alga Asparagopsis taxiformis (Delile) Trevisan.

How did it get to Adelaide? We have past records of drift plants at Port Stanvac and Marino, but no plants actually attached to rock, so wind and currents presumably have carried them west and north into Gulf St Vincent. Will climate change mean that in the future we might see this species growing on local rocky shores?

Sargassum decurrens, close-up. Photo: B. Baldock.

Sargassum decurrens is dark brown and tough, the main branches are strap-like with characteristic wings, flat-branched and end in thin, “leaves” and gas floats with fine, relatively long stalks. Our specimen is a particularly fine one and will be a welcome addition to the Herbarium’s collections.

Contributed by Hon. Research Associate Bob Baldock.

Sclerotium of Laccocephalum mylittae, dug up in March 2016. Photo: Danielle Calabro.

In late March 2016, Danielle Calabro, a Ranger at Flinders Chase National Park, Kangaroo Island, was digging up Bridal Creeper (Asparagus asparagoides) when she came across a dark brownish-black, monstrous lump approx. 0.5 m underground. Danielle dug it up and contacted Pam Catcheside, Hon. Research Associate at the State Herbarium of South Australia, who works on fungi, to ask if she knew what it was. Pam was able to tell her that it was a sclerotium, a tuber of one of the ‘fire fungi’, Laccocephalum mylittae. Danielle reburied the sclerotium and in late June she, Pam and others (David Catcheside, Flinders University, Helen Vonow, State Herbarium, and Teresa Lebel, National Herbarium of Victoria) who were over in Flinders Chase surveying fungi, went to dig up the fungus.

Sclerotium of Laccocephalum mylittae, held by Danielle Calabro and Pam Catcheside at excavation site, June 2016. Photo: David Catcheside.

Danielle had found the sclerotium in sandy soil under the branches of a fallen Eucalyptus cladocalyx in a disturbed, burnt area of the park. When exhumed, it was found to weigh 7.2 kg and measure 27 × 24 × 19 cm. The interior is white, marbled and solid. It was taken back to Adelaide and dried. Half will return to Flinders Chase, to be put on display at the Flinders Chase visitor centre. The remainder will be kept as an herbarium specimen (PSC 4459, AD-C60004).

Laccocephalum mylittae (Cooke & Massee) Núñez & Ryvarden, native bread, is one of the phoenicoid, the fire fungi, that fruit only after fire. In the case of L. mylittae the mushroom-like fruit body may emerge within a few days after fire.

Native bread is a member of the basidiomycete family, Polyporaceae. The whole fruit body is white to cream, often soil-stained. It consists of a cap which may reach 200 mm diameter, is irregular, flat to dome-shaped, smooth, soft but tough. It has pores, not gills, which are small and rather irregular. The stem is central to slightly off-centre, varies in length and diameter and is tough and solid. It leads down to a sclerotium, an underground tuber which has a dark brown to black skin and a white, marbled interior. Texture is rubbery initially but becomes hard and rather tough. The sclerotia may weigh up to 20 kg.

Site of sclerotium of Laccocephalum mylittae, March 2016. Photo: Danielle Calabro.

Laccocephalum mylittae is a saprotroph, breaking down woody substrates. It is a brown rot fungus, so called because it rots the wood, resulting in a brittle brown cubical mass.

Sclerotium of Laccocephalum mylittae, July 2016. Photo: Bob Baldock.

Fire stimulates the sclerotium to send up a fruit body. This produces spores which, if they land on a damp log, will germinate and form a mycelium, a mat of fine tubes called hyphae. The mycelium proliferates through the log and into the wood, sending the break-down products into the developing sclerotium, rather like the formation of a potato tuber. This sclerotium remains dormant under the soil, sometimes to depths of 0.5 m, until the next fire.

Laccocephalum mylittae produces a true sclerotium, one that is composed of only hyphal matter. Others of the so-called stone fungi, such as L. basilapiloides and L. tumulosum, produce a false sclerotium, one that is mixed with soil and grit.

References

1. Kalotas, A.C. (1996). Aboriginal knowledge and use of fungi. In Orchard, A.E. (Exec. Ed.), Mallett, K. & Grgurinovic C. (Vol. Eds.). Fungi of Australia, Vol. 1B: Introduction-Fungi in the Environment. (Australian Biological Resources Study, Canberra). (Pp. 284-286, as Polyporus mylittae).
2. Robinson, R. (2007). Laccocephalum mylittae – Native Bread. Fungus Factsheet 18 / 2007. (Dept of Environment & Conservation, WA) (500KB pdf).

See also fungi references listed in July’s Plant of the Month blog post.

Contributed by Hon. Research Associate Pam Catcheside.

Bands or zones of growth 10-20 cm wide on concrete walls of the West Beach marina, exposed at low tide and between waves. Upper green band of a wiry green alga (Chaetomorpha linum); lower band of red mat algae (L. monochlamydea and Gigartina brachiata). Photo: B. Baldock.

A diminutive turf-like red alga, Lomentaria monochlamydea (J.Agardh) Kylin, has been found growing as a band of turf on the concrete wall of the West Beach boat marina, Adelaide. This species has been known previously from asexual spore plants, but female and male plants have now been found for the first time in South Australia by State Herbarium Hon. Research Associate Bob Baldock and phycology staff member Carolyn Ricci. Why the excitement? — Well, descriptions of red algal species are never complete until the three separate plants – female, male and spore plants – have been found.

This alga has flattened, yet surprisingly, hollow branches and a growth pattern described by Allan Millar when he found it at Coffs Harbour in NSW as saltatory or “skipping” — an arched horizontal runner puts up vertical branches, pinched at the base, touches the rock or jetty pile surface, then continues on in “leaps and bounds” forming bright red, tangled mats.

Intertwined plants of L. monochlamydea (left) and the cohabiting red mat plant, Gigartina brachiate (right). The coin used as a scale is 23 mm across (or about 1” in diameter). Photos: B. Baldock.

For a while plants found at the West Beach marina were so intermingled with another intertidal red alga, Gigartina brachiata (tangled Gigartina), that we failed to spot that we were looking at two entities. Can you see the differences in the two images above? One is a littler darker in colour with more pointed branch tips?

Once back in the lab and sectioned under the microscope, features of the anatomy made identification easy. (This protracted procedure is often necessary and explains why getting an identification of an alga takes time — and experience.)

Silhouette view of a cluster of flask-shaped female structures at the base of a branch (left) and section view (right) with central mass of spores that grow into a separate asexual plant when released, continuing the life cycle of L. monochlamydea. Photo: B. Baldock.

Female structures after fertilisation produce bodies (actually separate stages vaguely like wombs and embryos in mammals) that look like miniature flasks. No “babies” are produced, however, just spores that germinate into sexless (asexual) plants when released through the opening in the duck-bill-like flask beak.

Male structures are pretty obscure — merely extremely small cells that ring each cortical or “skin” cell in patches on branch surfaces (see image below).

We have yet to locate a critical stage in female reproduction where a microscopic fertile cell (carpogonium) with a long terminal hair (trichogyne) snares a sperm cell floating past and fertilisation is accomplished, inducing the flask (cystocarpic) stage to develop.

Surface of a male plant. Extremely small spermatia form as rings around the larger surface cells. Photo: B. Baldock.

Lomentaria monochlamydea has not often been collected, so it is difficult to make a pronouncement about its distribution. It was first collected in Pt Phillip Bay, Victoria, is found along the NSW coast and there are a few female specimens in the Western Australia Herbarium (although these are attached to another red alga and may be a different species). Previously, in South Australia, it has been collected at the Pt Stanvac jetty and at Robe in shallow water.

Perhaps it has been overlooked or mistaken for Gigartina brachiata, as we initially did at the State Herbarium — which suggests there is a lot more searching and collecting still to come before closing the books on Lomentaria monochlamydea.