Fascination of Plants 2020

International Fascination of Plants Day, 18th May, has been celebrated since 2012 and has provided a focus for plant enthusiasts to share their interest and passion for the amazing world of plants. Last year events across 51 countries were held. While we are still primarily working from home the Staff and Honorary Research Associates of the Science and Conservation programme at the Botanic Gardens and State Herbarium (South Australia) decided to celebrate by sharing some of the plants they find fascinating!
Enjoy!
Michelle Waycott
Chief Botanist

Griffithsia monilis, a small, annual alga with delicate chains of ruby coloured cells, looking like sweets good enough to eat, spectacular under the microscope—Bob Baldock
Cephalotus follicularis (Albany Pitcher Plant), is a single species in its own family and endemic to near where I grew up in south Western Australia. These carnivorous plants are fascinating because they are not closely related to any of the other carnivorous plants such as Drosera (sundews)—Michelle Waycott
Ginkgo biloba, Royal Botanic Gardens Kew, on its 250th anniversary in 2012, with admiring cohort of ‘geriatric teenagers’—Pam Catcheside
Capparis spinosa ssp nummularia, I’m fascinated by the way the flowers change from bright white (to attract pollinators at night) to pink once its too late—Helen Vonow
Rhizanthella gardneri, an underground orchid. These fascinating plants flower where no-one can see them and only some animals can find them—that’s not an orchid! —Robyn Barker

CC BY 2.0 Fred Hort

Ptilotus sp. (mulla mulla), amazing combination of texture, colour and shape in this smoky pincushion—Teresa Lebel
Two bearded orchids from Mark Oliphant Reserve. One is Calochilus robertsonii, a bearded orchid. The other is Pterostylis plumosa, a bearded greenhood. Both are trying to trick insects into pollinating them. I like the thrill of the hunt of trying to find them 🙂 —Andrew Thornhill

Reflections—an ordinary little stump can be turned in to an intriguing complex pattern—Teresa Lebel
Acrotriche fasciculiflora (Mt Lofty Ground-berry) is fascinating for its cauliflory, with flowers packed around the base of its main stems, an adaptation for pollination or fruit dispersal by small vertebrates perhaps?—Peter Lang
Washingtonia robusta (Cotton Palms), native to Mexico, can be seen emerging from the skyline in older suburbs and rural towns in drier districts. An occasional though generally benign weed, it appeared in gardens and parks in the later 19th and early 20th centuries—Laurie Haegi
Tillandsia ‘Houston’ (T. stricta x T. recurvifolia) are fascinating because of their novel growth habit (air plants) and because they lend themselves so readily to decorative use around the home—Manfred Jusaitis
Hakea aenigma, found only on the western lateritic sands of Kangaroo Island, is sterile and unable to fruit. It resprouts after fires from suckers over distances of more than 30 km. A single plant that is an evolutionary dead-end but surviving for perhaps thousands of years—Bill Barker
Nuytsia floribunda, The West Australian Christmas Tree, is a parasitic plant that is actually a mistletoe! It has a unique way of parasitising the roots of nearby plants, a set of hard and sharp ‘shears’ cuts through the root so Nuytsia can attach feeding points to enable it get water and minerals from its hosts—Ainsley Calladine

 

 

Fire blog 6: The eucalypts will be back

Eucalyptus leptophylla, regenerating by regrowth from lignotuber, after fire in Billiatt Conservation Park, Murray Mallee. 18 June 2014. Photo: P.J. Lang.

The eucalypts are the epitome of resilience in surviving and regenerating after a bushfire. What first appears to be blackened and destroyed forests of tree trunks, returns as thousands of new shoots all over tree trunks and branches. It is almost without a doubt that the eucalypts have come to dominate Australia with the help of fire, given their ability to quickly recover from it. What do the eucalypts do that many of the other plants don’t, and what can we expect to see happen to eucalypts in the South Australian areas that have been burnt?

First of all, there is more than one way that eucalypts recover from fire. Some species recover by sprouting new leafy shoots all over their trunks and branches. This is called epicormic regrowth and is possible because many eucalypt species have buds buried deep below their bark that are protected from fire. It is triggered by the plant being under stress. Quickly regrowing leaves all over the burnt structure means that it is essentially functioning as a tree again and this is a massive advantage over other plants that have to regenerate from seed, to become a sapling, and then a tree, a process that can take years.

Eucalyptus cladocalyx, regeneration by epicormic regrowth, nearly 3 years after fire in Wanilla Conservation Park, Eyre Peninsula. 24 Sep 2007. Photo: P.J. Lang.

Other eucalypt species grow from lignotubers. A lignotuber is woody swelling at the base of a tree trunk. This structure can often be buried deep within the soil, another way of protecting a plant from fire. While the plant above the ground will be destroyed by a fire, the underground material remains untouched. New shoots appear from the lignotuber and the plant begins growing again from the ground up.

A third way that eucalypts can regenerate is from seed, and some eucalypts can only regenerate this way. This strategy involves plants growing from seedlings into adults, setting seed which falls to the ground and forms a seed bank. A fire then removes the adult plants and new seedlings are generated from the seed bank that then repeat the cycle. The risk of this strategy is that a second fire will occur while plants are seedlings or saplings that haven’t reached a stage to make new seeds, thus removing the species because there is no back-up seed bank. Eucalyptus regnans, the mountain ash of Victoria and Tasmania which is the tallest flowering plant in the world, is an obligate seeder.

Eucalyptus angulosa, regeneration from seed, nearly 3 years after fire in Murrunatta Conservation Park, Eyre Peninsula. Photo P.J.Lang.

With that quick crash course in regeneration strategies of eucalypts we can now turn our attention to South Australian species and what we can expect to see from them after a fire. In 2006 Dean Nicolle from the Currency Creek Arboretum published a paper that summarised the regenerative strategy of every eucalypt species. Below are two tables that are a subset of Dean’s work and give details for each native South Australian eucalypt in the Kangaroo Island (Table 1) and Adelaide Hills (Table 2) 2019/2020 fire zones. (A “combination sprouter”, listed in the tables below, can regenerate from both, epicormic shoots as well as from lignotubers.)

The good news is that not one of those eucalypt species is an obligate seeder and so the threat of a second fire in the next few years removing a species from these areas is not high. The majority of eucalypts in these areas have lignotubers and should successfully regenerate. There are things we need to be observant about though. We think that these fires were extremely hot in some areas, perhaps hotter than has ever been experienced before. While eucalypts are adapted for fire we are uncertain at what maximum temperature plants can survive and regenerate. Past fires have indicated that if the thermal tolerance of species is exceeded then they will not regenerate.

Compiled by State Herbarium botanists Andrew Thornhill and Peter Lang.

 

Table 1. Regeneration strategies of eucalypts of Kangaroo Island.

Taxon Lignotuber Habit Regenerative strategy
Eucalyptus albopurpurea Yes Mallee Lignotuber sprouter
Eucalyptus baxteri Yes Tree or facultative mallee Combination sprouter
Eucalyptus camaldulensis subsp. camaldulensis Variable Tree Sprouter (variable)
Eucalyptus cladocalyx No Tree Stem sprouter
Eucalyptus cneorifolia Yes Mallee Lignotuber sprouter
Eucalyptus cosmophylla Yes Tree or facultative mallee Combination sprouter
Eucalyptus diversifolia subsp. diversifolia Yes Mallee Lignotuber sprouter
Eucalyptus fasciculosa Yes Tree or facultative mallee Combination sprouter
Eucalyptus gracilis Yes Mallee or facultative tree Lignotuber sprouter
Eucalyptus leptophylla Yes Mallee Lignotuber sprouter
Eucalyptus leucoxylon subsp. leucoxylon Yes Tree Combination sprouter
Eucalyptus obliqua Yes Tree Combination sprouter
Eucalyptus odorata Yes Tree or facultative mallee Combination sprouter
Eucalyptus oleosa subsp. oleosa Yes Mallee Lignotuber sprouter
Eucalyptus ovata var. ovata Yes Tree or facultative mallee Combination sprouter
Eucalyptus paludicola Yes Tree or facultative mallee Combination sprouter
Eucalyptus phenax subsp. compressa Yes Mallee Lignotuber sprouter
Eucalyptus porosa Yes Tree or facultative mallee Combination sprouter
Eucalyptus remota Yes Tree or facultative mallee Sprouter (type unknown)
Eucalyptus rugosa Yes Mallee Lignotuber sprouter
Eucalyptus viminalis subsp. cygnetensis Yes Tree or facultative mallee Combination sprouter

 

Table 2. Regeneration strategies of eucalypts from the Adelaide Hills.

Taxon Lignotuber Habit Regenerative strategy
Eucalyptus baxteri Yes Tree or facultative mallee Combination sprouter
Eucalyptus camaldulensis subsp. camaldulensis Variable Tree Sprouter (variable)
Eucalyptus dalrympleana subsp. dalrympleana Yes Tree or facultative mallee Combination sprouter
Eucalyptus fasciculosa Yes Tree or facultative mallee Combination sprouter
Eucalyptus goniocalyx subsp. goniocalyx Yes Tree or facultative mallee Combination sprouter
Eucalyptus leucoxylon subsp. leucoxylon Yes Tree Combination sprouter
Eucalyptus leucoxylon subsp. pruinosa Yes Tree Combination sprouter
Eucalyptus obliqua Yes Tree Combination sprouter
Eucalyptus odorata Yes Tree or facultative Combination sprouter
Eucalyptus viminalis subsp. cygnetensis Yes Tree or facultative mallee Combination sprouter
Eucalyptus viminalis subsp. viminalis Yes Tree or facultative mallee Combination sprouter

New journal articles: May 2020

Hovenia dulcis. Line drawing by Anita Barley.

Today, the State Herbarium of South Australia published two articles in Vol. 33 of its journal Swainsona online.

(1)  J. Kellermann, Nomenclatural notes and typifications in Australian species of Paliureae (Rhamnaceae). (2.6mb PDF)

This is the first paper resulting from the ABRS funded research project on the plant family Rhamnaceae, undertaken by State Herbarium botanist Jürgen Kellermann and colleagues from around Australia. The nomenclature of the species of Hovenia and Ziziphus occurring in Australia is reviewed, including the role of the Paul Hermann herbarium in London; some plant names are typified. A key to the the Australian species, as well as line drawings are also provided.

(2) E.M. Davison, D. Giustiniano & J.F. Haska, Clarification of the type locality of Amanita peltigera (Agaricales, Amanitaceae), phylogenetic placement within subgenus Amanitina, and an expanded description. (2.3mb PDF).

The authors examined the native mushroom Amantia peltigera with molecular and morphological methods. They show that the type collection is from South Australia, not Western Australia, as stated in the original publication. They place the species in a phylogeny of the genus and provide a revised description and illustrations of A. peltigera.

Amanita peltigera, collected on Kangaroo Island. Photo: J.F. Haska.

To access content of all volumes of Swainsona and the Journal of the Adelaide Botanic Gardens since Vol. 1 (1976), please visit the journal’s web-site at flora.sa.gov.au/swainsona.

Fire blog 5: Floral wonderland – pretty flowers

In a previous blog, we introduced three species that often occur after fire.

Other attractive species likely to be seen on Kangaroo Island and elsewhere are branched everlasting, Coronidium adenophorum (F.Muell.) Paul G.Wilson, purple daisy bush, Olearia rudis (Benth.) Benth., as well as ironstone mulla mulla, Ptilotus beckerianus (F.Muell.) F.Muell., this last species appeared in hundreds in post 2007 fire scars near the Ravine des Casoars.

Coronidium adenophorum, Olearia rudis & Ptilotus beckerianus (from LEFT to RIGHT). Habit of plants with flowers and new seedling (for O. rudis). Photos: SA Seed Conservation Centre.

Contributed by State Herbarium botanist Martin O’Leary.

Fire blog 4: Fungi and fire

Orange disc fungus, Byssonectria fusispora, surrounded by mosses. Photo: D. Catcheside.

Fungi are essential in all ecosystems, acting as recyclers, helpers of almost all plants and improving soil health.  After fire, much of the organic material in soils may have burnt, leaving a blackened mass of fine, silty particles and ash. The ash is highly alkaline and unfavourable for plant regrowth. The fungi help in restoration of soil health, as recyclers of burnt litter and wood and as partners with plants in re-establishing the vegetation.

Two disc fungi, orange Pulvinula archeri, brown-lilac Peziza tenacella. Photo: D. Catcheside.

A group of fungi whose spores germinate almost immediately after fire are the disc fungi (e.g. Peziza and Pulvinula, image above). These act as colonisers. Their fine thread-like hyphae bind soil particles, stabilising the soil and helping to reduce erosion. They change the highly alkaline ash (with a pH of up to 10) to soils which are approximately neutral (pH 7). Structurally, the hyphae form a network, a ‘scaffolding’, improving soil aeration and water percolation. The often dense carpets of disc fungi covering the bare soil not only reduce erosion but also provide protection for small plants such as mosses, grasses and herbs (see top image). As the fungal hyphae and plant roots grow their developing networks increase movement of gases and water through the soil. Other groups of fungi are saprotrophs, breaking down and recycling burnt litter and wood.

Coprinellus angulatus, a saprotrophic fungus (left image). Stereum hirsutum, a saprotroph on wood (right image). Photos: D. Catcheside.

Pam Catcheside and Danielle Calabro with a sclerotium of Laccocephalum mylittae. Photo: D. Catcheside.

There is a definite succession of fungi after fires.

Amongst the first to appear, often only a day or two after fire, are strange, hard, mushroom-like fungi with pores, not gills in the genus Laccocephalum (see image at bottom of this post). Their fruit-bodies grow from an underground storage-organ called a sclerotium. The sclerotium of Laccocephalum mylittae, native bread, was eaten by Aborigines (image on right). It may weigh up to 20 kg.

Yellow, orange, brown and black disc fungi appear. Some species fruit only in the first year after fire, others in the second and some for several years. As litter builds up recycling fungi break it down returning nutrients to the soil.

Mycorrhizal fungi (e.g. from the genus Laccaria, image below), which form symbiotic relationships with plants become re-established, collecting nutrients and water for the partner plant and receiving energy-giving sugars in return. Gradually, the web of life with all its complex communication systems regains momentum, habitats are re-established, insects and other animal life return and natural cycles continue.

We observed this pattern after the 2007 bushfires on Kangaroo Island. Since Flinders Chase National Park is relatively self-contained, weeds which often invade bare areas did not threaten the native systems. Keeping out weeds after a fire is a major concern.

Laccaria sp., a mycorrhizal fungus. Photo: D. Catcheside.

Another concern is that it takes time for the bush to re-establish itself, some studies showing that it takes at least five years but this time lapse varies with different habitats. We have found that most groups of fungi have returned to pre-fire levels. It is now 12 years since the last major fires on the island and Kangaroo Island has shown itself to be resilient.

Laccocephalum sp. showing swollen sclerotium. Image of herbariumspecimen PSC3033 before drying. Photo: D. Catcheside.

Further reading

Atlas of Living Australia. Geopyxis carbonaria (Alb. & Schwein) Sacc.

Catcheside, P. (2009). Phoenicoid discomycetes in Kangaroo Island. Fungimap Newsletter 38: 5-8.

George, P. (2008). Fungimap survey on Kangaroo Island. Fungimap Newsletter 36: 13-15.

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).

McMullan-Fisher, S. J. M., May, T. W. & Keane, P. J. (2002). The macrofungal community and fire in a Mountain Ash forest in southern Australia. Fungal Diversity 10: 57-76.

Robinson, R.M. (2009). Laccocephalums on Kangaroo Island. Fungimap Newsletter 37: 6-7.

Robinson, R. (2007). Laccocephalum mylittae – Native Bread. (Dept of Environment & Conservation: Manjuimup). [Fungus Factsheet 18/2007].

Spooner, B. & Roberts, P. (2005). Fungi. (Collins: New Naturalist Library).

Yales, D. (2019). Fire-spawned forest fungi hide out in other organisms, study finds. PHYS.ORG website.

Written by State Herbarium Hon. Research Associate Pam Catcheside.