Category Archives: It’s All About the Plants

Life between the cracks

The mystery plant, Callitriche sonderi, between pavements. Photo: C. Brodie.

A group of botanists from the State Herbarium of South Australia had an interesting find while walking in Adelaide Botanic Garden recently. Chris Brodie, a botanist specialising in non-native plants of South Australia was scanning around, always on the lookout for weeds. In the crack between two brick pavers he saw a tiny plant and got down on hands and knees for a closer look. Carolyn Ricci, Tracey Spokes and Peter Lang came over to see what he had found, all were down peering at the tiny green plant. The sight of four mature adults crawling around on the pavers attracted some strange glances and extreme social distancing from passers-by! The plant was very small and intriguingly no one knew for sure what it was. Chris took some photos on his smartphone of an entire plant and zoomed in on the strange dark markings on the leaves.

Callitriche sonderi, fungal infection in leaf veins. Scale bar = 2 mm. Photo: P. Lang.

Seeing the magnified images, Peter suggested the dark leaf areas might be a fungal infection. Carolyn located further specimens nearby, it was then noted to be reasonably common in that area. A sample was taken for investigation.

On returning to the State Herbarium, Chris took a look at the sample under a microscope and was pleased to see the sample contained both flowers and fruit (these are often necessary for accurate identification of plant species). The plant was identified as a species of Callitriche. The fruit are the definitive characters for identifying species in this genus. The plant was not a weed at all, but a native species named Callitriche sonderi (formerly in Callitrichaceae, now in the family Plantaginaceae). A check of the SA Plant Census revealed the species is currently listed as Rare in South Australia.

Callitriche sonderi, flowers with style and pollen. Scale bar = 1 mm. Photo: P. Lang.

Peter used a digital image stacking process using a camera attached to a microscope to increase the depth of field shown in the macroscopic images of the plant.

It is good practice to look at other specimens in the collection to confirm identifications, and a search revealed that most of the Herbarium’s Callitriche specimens had been loaned to Richard V. Lansdown, a researcher at Kew and a world expert on the genus. Fortunately the loan had recently been returned and was being processed prior to its placement back in the vault. (Herbarium policy requires return loan material to be frozen to exterminate any pests that may have infiltrated the specimens in transit prior to returning to the collection). An Australian treatment published in 2007 by A.R. (Tony) Bean at the Queensland Herbarium indicated some changes to existing species concepts. Using the key to all Australian native and alien Callitriche species in Bean’s revision, and referring to the re-determined loan specimens returned from Kew, Peter and Chris were able to confirm that the pavement specimen remained within the species concept of Callitriche sonderi.

Callitriche sonderi, fruits. Scale bar = 1 mm. Photo: P. Lang.

Meanwhile Teresa Lebel, a mycologist and specialist in truffle-like fungi, Agaricus and Russulales at the State Herbarium, was consulted regarding the dark markings on the leaves and confirmed Peter’s hunch that it was indeed a fungal infection, most likely a smut fungus. Teresa, Carolyn and Bob Baldock took pictures of the fungal spores using a compound microscope with an attached camera. During this process they discovered an abundance of pollen, predominantly Pinus spp. and a few moss spores. Teresa consulted a colleague — Roger Shivas, a Plant Pathologist and Mycologist with a specialty in rusts, smuts and other microfungi at the Plant Pathology Herbarium at the Queensland Department of Agriculture and Fisheries. Roger referred Teresa to a smut fungus Doassinga callitrichis found on Callitriche stagnalis in Germany, this being the only known smut/Callitriche association in his experience. However, Teresa’s investigations revealed that the Botanic Gardens smut does not affect the Australian Callitriche in the same way, and microscopically does not resemble the description of Doassinga callitrichis. Teresa and Roger are now planning a collaboration to research this potentially new species of smut fungus and new plant/fungal association.

Spores of the unknown smut fungus. Photo: B. Baldock.

While walking through the botanic gardens Tracey found another population of Callitriche sonderi growing between the pavers some 200 metres from the first find. This leaves us wondering if Callitriche sonderi is rare in South Australia or, because of its small size, it is rarely seen and collected.

Written by Herbarium staff member
Tracey Spokes.

Preliminary studies of the fungi in Flinders Chase National Parks after the 2020 fires

Peziza aff. petersii. Photo: David Catcheside.

Fungi play important roles after fire. Their fine, root-like hyphae bind soil particles, stabilising the soil and reducing erosion. Fungi provide nutrients for plants, helping to re-establish plant communities. They reduce the high pH of the ash bed. Many fungi break down the burnt litter and wood, returning nutrients to the soil. A previous Blog on fires and fungi in Flinders Chase National Park was written before a recent survey of the Park.

Plicaria recurva. Photo: David Catcheside.

In mid-July 2020, Pam and David Catcheside surveyed the fungi in Flinders Chase National Park, devastated after the previous summer bushfires. These surveys augment those made after the 2007 bushfires in the Park (see references below) and enable comparisons to be made of the fungi fruiting after those fire events. In 2020, 96 % of Flinders Chase was burnt, more than the 85 % estimate for the 2007 fires. Preliminary analysis suggests that, although there is some overlap between the species that occurred after the 2007 and 2020 fires, there are differences both in species composition and species richness, perhaps reflecting the differences in severity of the fires.

Pulvinula archeri. Photo: David Catcheside.

In 2020, collections were made at a number of sites, all of which had been severely burnt: near Rocky River, Platypus Waterholes, the Ravine des Casoars, Gosselands and Kelly Hill Conservation Park. The fungi were similar at all sites, though fruiting was less at Gosselands and at Kelly Hill.

Disc fungi made up most of the fungi that were found. These fungi are important colonisers often fruiting in profusion soon after fire. They reduce the strongly alkaline pH (around pH 10) resulting from the ash closer to neutral (pH 7), a pH more favourable for plant growth. The most common species were a fawn to pinkish-brown species of Peziza, possibly P. petersii, black-brown Plicaria recurva (see images above) and the small, brilliant orange Pulvinula archeri. There were a few patches of orange Anthracobia maurilabra and A. muelleri.

Anthracobia aff. maurilabra. Photo: David Catcheside.

After the 2007 fires, Anthracobias were abundant, often in circles around the bases of Xanthorrhoea semiplana var. tateana in contrast with the few patches seen in 2020. Also after the 2007 fires Pulvinula archeri, though present, was not in the profusion found in 2020. Disc fungi are often difficult to identify to species. Almost all require microscopic examination of often nuanced characters such as spore ornamentation. Samples of some of the disc fungi collected have been taken for molecular sequencing and analysis. Results should help to clarify the tentative identifications made so far on the collections.

Laccaria aff. canaliculata. Photo: David Catcheside.

A few gilled fungi were found, including a species of Laccaria. Laccarias are early colonisers of burnt and bare ground and are mycorrhizal, forming essential partnerships with plants.

In contrast with the fungi found after the 2007 fires, there were few fruit bodies of ‘stone fungi’, species of Laccocephalum. Their hard, pored, mushroom-like fruit bodies come up almost immediately after fire from a sclerotium, an underground storage tuber. This year, fruit bodies of Laccocephalum tumulosum, the only species of Laccocephalum found, were much smaller than those seen after the 2007 fires, reaching only 5 cm in comparison with the up to 20 cm of the 2008 collections. In 2008 and 2009 five species of Laccocephalum were collected: L. tumulosum, L. mylittae, L. basilapiloides, L. minormylittae and L. sclerotinium. Their sclerotia can be mixtures of fungal tissue and sand (false sclerotia) or consist only of fungal tissue (true sclerotia).

Laccocephalum tumulosum. Photo: David Catcheside.

At one site at the Ravine des Casoars, an undescribed species of coral fungus, Ramaria or Ramariopsis, was pushing up the sandy soil over an area of several metres. When excavated, this fungus was seen to have a false sclerotium, a structure previously unknown for any species of coral fungus (see images below).

Fungal fruiting is rain and temperature dependent and it is difficult to select the optimal time for surveys and collections. June and July are usually good months for fungi in South Australia. In 2008 Pam and David spent a week in early June when they collected 14 species of disc fungi, approximately 17 species of gilled fungi, two boletes (soft pored fungi with a central stem), a few club, bracket and coral fungi, in all approximately 40 species. The conditions prior to their collecting trip in 2020 were dry and would have had a somewhat detrimental effect on fungal fruiting. Nonetheless, the results were unexpected: only nine species of disc fungi, four of gilled fungi, two coral fungi with a total of 18 species. These preliminary results from the two sets of surveys suggest that both species composition and richness are less after the more extensive and more severe summer fires of 2020.

Ramaria sp. Sclerotium (left) and habit (right). Photos: David Catcheside.

References

Catcheside, P.S. (2009). The phoenicoid discomycetes on Kangaroo Island. Fungimap Newsletter 38: 5–7 (1.2mb PDF).
Catcheside, P.S., May, T.W. & Catcheside, D.E.A. (2009). The larger fungi in Flinders Chase National Park, Kangaroo Island. Surveys 2008. Report for Wildlife Conservation Fund and Native Vegetation Council.
Catcheside, P.S. & Catcheside, D.E.A. (2010). The larger fungi in Flinders Chase National Park, Kangaroo Island. Surveys 2009. Report for Wildlife Conservation Fund and Native Vegetation Council.

Contributed by Pam Catcheside (State Herbarium Hon. Associate)
& David Catcheside (Flinders University).

Collecting mosses and fossils in the Gurbantünggüt Desert of north-western China

It’s All About the Plants
Tuesday, 19 July 2016, 10:30–12:00
Goodman Building Lecture Theatre,
adjacent to the State Herbarium of South Australia
Adelaide Botanic Garden, Hackney Road

by Alison Downing
Department of Biological Sciences, Macquarie University, NSW

Biologists from the Key Laboratory of Biogeography and Bioresources in Arid Lands, Xinjiang Institute of Ecology and Geography in far north-western China, have been studying biological soil crusts typical of the deserts of this region for more than a decade. An invitation to join a Chinese-led, international team of palaeontologists studying crinoids in marginal desert lands of north-western Xinjiang led also to an unexpected invitation to work with Chinese scientists on soil crust biology of the Gurbantünggüt Desert.

Gurbantünggüt Desert, Photo: Wang Ao.

Understanding the biology of desert soil crusts can provide useful tools for the management of arid lands where soil crusts play a major role in minimizing erosional processes and in doing so, reducing sandstorm frequency and the associated costs of adding to pollution in the major cities and towns of eastern China.

Alison will give a brief introduction to some of the studies in which she has been involved, and also a glimpse of some of the spectacular landscapes of north-western China. Don’t expect water buffaloes, lotus and rice paddies; rather camels, deserts, forests of spruce and birch, and snow-capped mountains…

Alison Downing is a Senior Research Fellow in Biological Sciences at Macquarie University. She completed her Masters degree on karst bryophytes in 1993 and continued with that work and other allied interests, such as Pottiaceae and bryophytes of biological soil crusts, ever since. Besides her collaboration with Chinese researchers on desert soil crusts she also is working on subantarctic bryophytes, at the other end of the world. Current projects include the role of bryophytes in determining strategies for the long term management of subtropical rainforests in eastern Australia.

At a time when academic staff at universities around the world are more and more frustrated by increasing administrative work, her present position allows Alison greater opportunities to facilitate local and international collaborative studies. She also likes promoting bryology to the general public to overcome many of the less favourable preconceptions about bryophytes. Alison is a Council Member of the International Association of Bryologists.

Keeping your “eggs” in one basket

Cyanthus olla with “eggs”. Photo: Bob Baldock.

State Herbarium Hon. Research Associates Pam Catcheside and Bob Baldock report another cryptic and appealing fungus. It has appeared in the Botanic Gardens, this time amongst bark chips associated with recent plantings of pistachio saplings adjacent to the Old Tram Barn. A previous BLOG article described the coral fungus, Aseroe rubra Labill.

It is a birds nest fungus, easily passed over by the casual visitor to the gardens, but worth close inspection. Its Latin name, Cyathus olla (Batsch) Pers., literally means “cup” and “pot”. The bulk of the fungus occurs as cryptic, microscopic threads (the mycelium), infiltrating and busily dissolving the wood and bark chips for food. But the mature fruiting body is visible to the keen observer.

Cyanthus olla. Photo: Bob Baldock.

At first a ball-shaped structure forms. Then the membranous top tears to reveal a hollow interior with 8 to 10 grey-black “eggs” at the bottom of a fruiting body about 10 mm across which becomes goblet-shaped. The outside is grey-brown, covered with fine hairs at first, but it may later become smooth. Each “egg” is a spore packet a mere 3-5 mm by 1-2 mm, attached to the sides of the cup by fine elastic threads (unfortunately not visible in the images provided). At this minute scale, raindrops falling inside the “nest” have enough force to fling the “eggs” and their threads up and 1 m away from the fruiting body − a small-scale but violent dispersal mechanism! The elastic threads act like the boluses of South American gauchos and wrap around any available obstruction as the “eggs” land, securing them in place.

Cyanthus striatus. Photo: David Catcheside.

The fluted birds nest fungus, Cyathus striatus (Huds.) Willd., also appears occasionally on wood mulch in the Botanic Gardens. The cups are similar in size to those of C. olla but their outer surfaces are covered with brown, shaggy hairs, and the inner surfaces are grooved or fluted, hence the name striatus.

Other birds nest fungi, Nidularia and Crucibulum species, lack elastic threads and have their “eggs” embedded in mucilage, but like Cyathus, rely on raindrops for dispersal.

Field to database—documenting the flora of Melanesian Islands

It’s All About the Plants
Tuesday, 8 March 2016, 10:30–12:00
Goodman Building Lecture Theatre,
adjacent to the State Herbarium of South Australia
Adelaide Botanic Garden, Hackney Road

by Shelley A James
iDigBio, Florida Museum of Natural History, USA

ShelleyJ_pressing Dr James’ research interests focus on the diversity and biogeography of the flora of the Pacific region. For more than six years, she has been undertaking field work in Papua New Guinea and, recently, the Solomon Islands, collecting new botanical specimens in remote locations, and digitising herbarium collections from the Pacific. Now working for iDigBio (Integrated Digitized Biocollections), the US initiative mobilising biological specimen data, she liaises between museum collections staff, researchers, educators and cyberinfrastructure to promote the use of natural history collections and the data they contain in answering big science questions.

Previously, Shelley was a botanist in the Herbarium Pacificum and manager of the Pacific Center of Molecular Biodiversity at the Bishop Museum in Honolulu, Hawai’i.