April 2019


Volume 46 No 3

Calendar

April
Sat 27 2-4pm Bimonthly meeting at Gumnut Hall, Gumnut Place Cherrybrook with guest speaker Ray and Elma Kearney on ‘Cooperation between animals, Plants and Fungi in Nature’

May
Mon 4 All submissions for Calgaroo welcome.
Wed 8 Propagation at Bidjiwong Community Nursery 10am to 1 pm
Sat 27 Bushwalk, Lane Cove National Park Fungi

June
Wed 12 10am to 1pm. Propagation at Bidjiwong Community Nursery
Sat 22 2-4pm Bi-monthly Meeting at Gumnut Hall Gumnut Place


The North Rocks Shopping Centre Stall, 30th March 2019

This was our second stall held at North Rocks shopping centre and we were given a good spot, right outside Coles. The tables were filled with plants, almost none of which were in flower (the disadvantage of an autumn sale), but we had several photo labels rising above the greenery which did their job in attracting buyers. We had plenty of interested people stop for a chat, ask lots of questions, show interest in our group and buy plants, so all in all it seemed to be a success. We raised $369, and hopefully some of those who expressed an interest will come along to our meetings and join our group.

Thank you to the wonderful helpers who were able to find some time for the group out of their already busy lives – Grahame, Sue, Marilyn, Ian, Edwin, Caroline, Jennifer and Pip. I think we might be doing this again!

Lesley


Don’t forget to bring your reusable mug with you to our meetings – we need to reduce plastic going to landfill and damaging our environment.


APS NSW Annual General Meeting and Quarterly Gathering – Saturday, 18 May 2019

Hosted by the Blue Mountains Group, at Blaxland Community Hall, 33 Hope St., Blaxland

AGM at 12.30pm
Talk from 1 – 3pm

Featuring: Plants with a Bite

Keen to find out about Australian carnivorous plants, what they are, what they eat, how they capture their prey and how to grow and maintain them in cultivation? So little is known about these plants, yet Australia has one of the world’s richest carnivorous plant floras.

Our guest speaker Greg Bourke, who has an unbridled passion for these highly unusual plants, will answer all your questions.


Have you noticed ginger syndrome in eucalypts? It’s here in NSW too.

ABC Rural Rose Grant
Posted 26 February 2015 at 1:37 pm

Extreme heat in northern Tasmania is transforming the look of the bush. From Smithton to Bridport, thousands of eucalypts (mainly white gums and blue gums) have died or are stressed and leaking sap from their bark…

Read more here:

https://www.abc.net.au/news/rural/2015-02-26/ginger-tree-syndrome/6263118


Silver moss is a rugged survivor in the city landscape

Alison Haynes March 22, 2019

Silver moss growing on a Wollongong basketball court.

Chances are you’ve walked over silver moss (Bryum argenteum) countless times without giving it a second glance. This moss, at home in moist environments as well as hot and cold deserts, is also a common denizen of cities worldwide and finds shelter in our pavement cracks.

Also known as silvery thread moss and silvergreen bryum moss, it grows in all states and territories of Australia, particularly in towns and cities.

To the naked eye, it appears as a tiny silvery green ribbon or small cushion, with stems up to 1.5cm tall, but often only a few millimetres high. With a hand lens, its crowded, tight buds are visible, while a microscope reveals the reason for its silvery appearance: cells in the top portion of its minute leaves do not have chloroplasts (and therefore no chlorophyll) and do not appear green, but instead make a transparent silvery tip. This portion of the leaf protects the chloroplasts deeper down from harsh sunlight.

Like many others in its genus, the leaves have a rounded appearance with a central rib, or costa, that ends well before the tip. As with most moss, these simple leaves are only one cell layer thick, so it exchanges gases and water with the exterior by diffusion.

The silver moss is a survivor. We remove native vegetation from our cities and clear forest canopies but it can cope with this new version of home. We swap forest floor for hard, impervious surfaces that utterly change how water moves across the landscape – for instance, evaporating much more quickly – but this moss makes use of water when it can, switching on its photosynthesis processes when there’s enough water, and hunkering down when there’s not.

This cycle can occur over the duration of a day, with photosynthesis starting in the early morning light when there’s a little dew on the leaves, and closing down as the day progresses and the moss dries, but it can also play out over much longer periods, even years.

It can do this thanks to its particularly strong tolerance for desiccation, a trait which varies across moss species. This isn’t just the ability to withstand drought. It’s more radical than that. It is the ability to shut down all metabolic processes in the absence of water, and start them up again when water is available. This might not sound too impressive, but in the majority of plants drying out totally involves serious damage at the cell level, with membranes and cell organelles becoming brittle and breaking and macromolecules such as DNA being damaged beyond repair.

Silver moss uses sugars to create protective glass-like compounds to protect its cells from irreparable damage. Because of its tough nature, the silver moss is widely studied to further understanding of how plants cope with a range of other stresses too, from UV-B radiation and sand burial to trace metals and excessive light.

Silver moss is not showy and quite often looks rather dusty in city environments, but it’s nice to know that the 19th century botanist Ferdinand von Mueller collected it twice in 1852, in Adelaide, five years after his arrival from Germany. He moved to Melbourne that year, was appointed government botanist, and founded the National Herbarium of Victoria a year later, in 1853. These two samples must have been among the first deposited there, making them our oldest specimens of this species in Australia.

While I don’t know exactly what species were used, Aboriginal Australians took advantage of the moisture that moss collects. In Queensland, for instance, Indigenous people used to squeeze out water from a moss clump then replace it carefully, to use again.

For me, moss is on the cusp of the macro and micro world. Just big enough to see with the naked eye, it nonetheless draws you in and down to a smaller world. I’ve become a moss tourist. Whenever I go to a city, I don’t just look up at the sights, I also look down! Mosses like Bryum argenteum remind me of the wild even within the depth of a city landscape. They are a reminder that we may remove native forests, but still the most minute spores of living organisms will come in and find a place to live, if not thrive.

This article first published at The Conversation – theconversation.com


Olive Pink

Olive Pink was a botanical painter who had a passion for Australia’s arid plants, particularly those of central Australia, and advocated for their recognition for most of her life. Olive permanently moved to the Northern Territory in 1943 and eventually she set up a small museum to exhibit some of her artworks and arid plant specimens.

Olive Pink’s painting of quandong: Australia’s arid Santalum acuminatum plants

Sidney Nolan was one of many notable visitors. In 1956, Olive was evicted from the army hut she lived in and was later given a license to pitch a tent on a vacant plot, now the land on which the Olive Pink Botanic Garden, Alice Springs, lies. It showcases the best of

Read about this amazing “Woman in Botany” and many others, including Ellis Rowan, Edith Coleman, Mary White, Georgiania Molloy, Fran Bodkin, The Scott Sisters, Janet Cosh and Thistle Harris among others on the Australian Geographic website at –

https://www.australiangeographic.com.au/topics/history-culture/2019/03/17-incredible-australian-women-in-botany/


Are more Aussie trees dying of drought? Scientists need your help spotting dead trees

As climate change threatens Australian trees, it’s important to identify which are at risk.

Authors

  • Belinda Medlyn Professor, Western Sydney University
  • Brendan Choat Associate Professor, Western Sydney University
  • Martin De Kauwe Senior Research Fellow, UNSW

Most citizen science initiatives ask people to record living things, like frogs, wombats, or feral animals. But dead things can also be hugely informative for science. We have just launched a new citizen science project, The Dead Tree Detective, which aims to record where and when trees have died in Australia.

The current drought across southeastern Australia has been so severe that native trees have begun to perish, and we need people to send in photographs tracking what has died. These records will be valuable for scientists trying to understand and predict how native forests and woodlands are vulnerable to climate extremes.

Understanding where trees are most at risk is becoming urgent because it’s increasingly clear that climate change is already underway. On average, temperatures across Australia have risen more than 1℃ since 1910, and winter rainfall in southern Australia has declined. Further increases in temperature, and increasing time spent in drought, are forecast.

How our native plants cope with these changes will affect (among other things) biodiversity, water supplies, fire risk, and carbon storage. Unfortunately, how climate change is likely to affect Australian vegetation is a complex problem, and one we don’t yet have a good handle on.

Climate niche

All plants have a preferred average climate where they grow best (their “climatic niche”). Many Australian tree species have small climatic niches.
It’s been estimated an increase of 2℃ would see 40% of eucalypt species stranded in climate conditions to which they are not adapted.
But what happens if species move out of their climatic niche? It’s possible there will be a gradual migration across the landscape as plants move to keep up with the climate.
It’s also possible that plants will generally grow better, if carbon dioxide rises and frosts become less common (although this is a complicated and disputed claim.)
However, a third possibility is that increasing climate extremes will lead to mass tree deaths, with severe consequences.

There are examples of all three possibilities in the scientific literature, but reports of widespread tree death are becoming increasingly commonplace.

Many scientists, including ourselves, are now trying to identify the circumstances under which we may see trees die from climate stress. Quantifying these thresholds is going to be key for working out where vegetation may be headed.

The water transport system

Australian plants must deal with the most variable rainfall in the world. Only trees adapted to prolonged drought can survive. However, drought severity is forecast to increase, and rising heat extremes will exacerbate drought stress past their tolerance.

Lyn Lacey submitted these photos of dead trees at Ashford, NSW
to The Dead Tree Detective.

To explain why droughts overwhelm trees, we need to look at the water transport system that keeps them alive. Essentially, trees draw water from the soil through their roots and up to their leaves. Plants do not have a pump (like our hearts) to move water – instead, water is pulled up under tension using energy from sunlight. Our research illustrates how this transport system breaks down during droughts.

In hot weather, more moisture evaporates from trees’ leaves, putting more pressure on their water transport system. This evaporation can actually be useful, because it keeps the trees’ leaves cool during heatwaves. However if there is not enough water available, leaf temperatures can become lethally high, scorching the tree canopy.

We’ve also identified how drought tolerance varies among native tree species. Species growing in low-rainfall areas are better equipped to handle drought, showing they are finely tuned to their climate niche and suggesting many species will be vulnerable if climate change increases drought severity.

Based on all of these data, we hope to be able to predict where and when trees will be vulnerable to death from drought and heat stress. The problem lies in testing our predictions – and that’s where citizen science comes in. Satellite  remote  sensing can help us track overall greenness of ecosystems, but it can’t detect individual tree death. Observation on the ground is needed.

These images show a failure of the water transport system in Eucalyptus saligna. Left: well-watered plant. Right: severely droughted plant. On the right, air bubbles blocking the transport system can be seen. Brendan Choat

However, there is no system in place to record tree death from drought in Australia. For example, during the Millennium Drought, the most severe and extended drought for a century in southern Australia, there are almost no records of native tree death (other than along the rivers, where over-extraction of water was also an issue). Were there no deaths? Or were they simply not recorded?

The current drought gripping the southeast has not been as long as the Millennium Drought, but it does appear to be more intense, with some places receiving almost no rain for two years. We’ve also had a summer of repeated heatwaves, which will have intensified the stress.

We’re hearing anecdotal reports of tree death in the news and on twitter. We’re aiming to capture these anecdotal reports, and back them up with information including photographs, locations, numbers and species of trees affected, on the Dead Tree Detective.

We encourage anyone who sees dead trees around them to hop online and contribute. The Detective also allows people to record tree deaths from other causes – and trees that have come back to life again (sometimes dead isn’t dead). It can be depressing to see trees die – but recording their deaths for science helps to ensure they won’t have died in vain.

This article first published at The Conversation, theconversation.com March 26, 2019 1.58pm EDT


Plant Profile: Eucalyptus piperita – Sydney Peppermint

Latin piperitus = pepper- like (peppermint aroma from leaves)

HABIT/HABITAT: A medium- tall tree up to 30 m. In dry sclerophyll forest or woodland.

BARK: Persistent bark, shortly fibrous grey -brown on trunk and large branches. Upper branches smooth white, shedding in long ribbons.

LEAVES: Adult leaves falcate, lanceolate, dull green, concolorous with a strong peppermint aroma.

BUDS Operculum of the bud is quite pointed

FLOWERS: white or cream in dense clusters.

FRUIT: Capsule globose, ovoid or urceolate with a small orifice.


A Visit to Inverawe Native Gardens

Billed as the largest landscaped native gardens in Tasmania, “Inverawe” is amazing. Bill and Margaret “retired” to a large steep property descending to the shores on North West Bay, about 20 Kms south of Hobart. They have constructed gardens, paths, paving and flights of steps crisscrossing the slope, winding down the water’s edge. They have planted hundreds of natives, blending in with natural bush nearer the water. Tom and I visited in March, when not many plants were likely to be in flower, and with Tasmania trying to survive a long drought. The state was not the green haven we expected.

The variety of native plants in this garden is wide. Certain species obviously do well, especially Correas. There were lots of different grevilleas. Some Western Australian plants do much better that in Sydney, such as large ungrafted Eucalyptus ficifolia and Adenanthos sericea. Paper daisies were flowering in a variety of colours. The garden is enhanced by sculptures and figures, some with whimsy and humour. Bill writes poetry which is scattered amongst the plants. Margaret serves morning and afternoon teas, and is happy to chat and answer questions. They sell plants

and items like flower cards. I don’t know where this couple find the time and energy. If you are ever in Hobart, don’t miss this wonderful garden.

From Pip Gibian

Socrates and Aristotle
Garden included many paths
Correas do very well in this garden
One of many paper daisies in flower
Botanists Brown and Billardiere
Healthy plants near the house

Melton Botanic Garden

By David and Barbara Pye

The Melton Botanic Garden is Melbourne’s newest Botanic garden. The garden occupies 24 hectares and is based in the driest part of the Melbourne region. Annual rainfall is 450-500 mm long term, but in recent times has often been around 300 mm. Soils are generally moist in winter and dry in summer. The garden is well suited to growing plants from dryland regions.

The garden is being developed by the Friends of the Melton Botanic Garden (FMBG) with support from Melton Shire Council, Matchworks and various other community groups. It houses a collection of dryland Eucalypts which includes more than 100 species, most of which are suitable for suburban and town gardens.

Six years ago, we set out to plant a Eucalyptus arboretum with dryland species (ie from less than 450 mm rainfall zones). Many of these established quickly and have flowered several times. Because of their relatively small size and masses of colourful flowers they have proved popular with the ever increasing number of visitors to the garden. In general, the Eucalypts were planted in groups of 3-5 plants, with an understorey of various colourful shrubs, including Eremophilas and local everlasting daisies (Chrysocephalum and Xerochrysum species).

Eucalyptus youngiana Yarldarlba

Eucalyptus youngiana Yarldarlba

Mallee to 8 m tall, sometimes trees to about 10 m. Forms a lignotuber. Rough bark over part or all of trunk, smooth above, whitish grey over yellowish or salmon pink, dull light green leaves, Large red, pink or bright yellow flowers, large distinctive fruits.

Distribution: Western Australia

Eucalyptus megacornuta Warted yate

Eucalyptus megacornuta Warted yate

Mallet to 15m tall – no lignotuber.
Smooth bark throughout. Large warty buds, flowers yellowish green.

Distribution: Western Australia

From the ANPSA Eucalyptus Study Group Newsletter July 2017, No. 69


Parramatta and Hills District Group

SECRETARY: Caroline Franks

Email: apsparrahills@gmail.com