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..odds and ends from the world of Australian plants....
Return of the Birds
|Australian growers of Australian plants have always known that a great variety of birds are lured into gardens by the attractions offered by the plants. The most obvious of these attractions is the nectar produced by the flowers of many plants such as banksias, bottlebrushes, grevilleas and correas. But other features are important too, such as the protection offered small birds by plants with prickly foliage and the insects that feed on the leaves and which, in turn, become food for shrike thrushes, robins and many others.
It seems now that the media at large might be finally becoming aware of this phenomenon. An article in the Sydney Daily Telegraph of 10 January 1997 ("Birds flock back into gardens") reports on the increased sightings of birds such as rosellas, lorikeets, parrots and honeyeaters. "Sydney has become a fantastic city for birdwatchers", claims Penny Drake-Brockman, of the NSW Field Ornithologists Club. "The native trees and shrubs planted 20 years ago, have matured.....so there is much more cover and food for the birds."
According to Peter Roberts, author of the "Birdwatchers Guide to the Sydney Region", more than 280 bird species can be found in the Sydney area. This variety is due to the wide range of habits available. Even rare species are being sighted in popular areas such as Centennial Park and the Royal Botanic Gardens.
With Wattle day (September 1) just passed, it's probably not a bad time to look at the myths surrounding the connection between wattle (Acacia species) and hay fever. It's a commonly held view that pollen from acacias causes hay fever. But is this, in fact, the case?
Latest information suggests that, for the majority of people, the answer is "Probably not"!
In response to an enquiry by the Society, Dr Diana Bass, an expert in allergenic diseases, commented that a study of airborne pollen in Canberra showed air borne wattle pollen to range from 1-3 grains per cubic metre of air in July rising to a peak of 17 grains per cubic metre in October. In contrast, grass pollen may reach 80-200 grains per cubic metre in late October to early December. Dr Bass indicated that the wattle pollen count was sufficient "to cause (allergic) symptoms in sensitized subjects" but that she tested every patient with wattle extract and seldom found a significant reaction.
Similar comments have been made by Dr J Youngman, the Deputy Director-General (Health Services), Queensland. Dr Youngman indicated that "The prevalence of wattle sensitivity is less common than is the prevalence of sensitivity to common grass pollens". Furthermore, "As wattle pollens are relatively large and heavy, they are not readily distributed by the wind in comparison to the smaller and lighter grass pollens".
Circumstantial evidence? Have wattles such as Acacia pubescens been wrongly maligned? Select the thumbnail image or plant name for a higher resolution image (30k).
So the next time you get a dose of the "spring sneezes", don't blame your neighbour's Cootamundra Wattle. Maybe it's due to the grass on your side of the fence.
An Unexpected Connection
When I received an unsolicited email from someone offering to write an article on the flora of the Flinders Ranges in South Australia I was, of course, delighted. When I took a closer look at the email address of the correspondent and noted that it originated in Ireland, I was a bit puzzled. Then when I noted that the correspondent's name was a very un-Gaelic "Horst" I knew I had to get to the bottom of this!
Horst Weber is a German who works for the German Cultural Institute, Goethe-Institut in Dublin. Some years ago Horst visited Arkaroola in the northern Flinders Ranges and was captivated by the landforms and the flora. He has returned on a number of occasions and should be making another visit as this edition of "Australian Plants online" is released. The impact of the area was such that Horst has written a booklet about the area which is a guide to the walking trails and the flora.
The article "Quandong" in this issue is based on one of the chapters of the booklet which Horst expects to publish later this year or in early 1998. If you are interested in the booklet, a contact address will be found at the end of the article.
New cultivars of Australian plants appear at regular intervals, some aimed at the commercial cut flower grower and others at ornamental horticulture. Some will become firmly established in gardens and others will disappear without trace....
Here are a few which have appeared recently. Keep a look out for them at your favourite nursery:
|Leptospermum liversidgei "Mozzie Blocker"||An unusual plant - selected for the high concentration of citronellal in its foliage. Citronellal apparently repels mosquitoes, hence the name. The plant has pink flowers and can reach 1.8 metres.|
|Scaevola aemula "Blue Fandango"||A more or less upright growing form of this normally prostrate species. It is small, herbaceous plant growing to 30 cm x up to 50 cm spread. The typical "fan" shaped flowers are 30 mm diameter and violet in colour.|
|Agonis flexuosa "Southern Wonder"|| A variegated selection of this large, weeping shrub. The leaves are dark green, edged with cream and have reddish stems.|
|Westringia "Sea Mist"|| Another variegated plant with mauve flowers in winter and spring.|
These are a few items from various sources. Please send any similar items that you think could be of interest to other readers.
|World's Oldest Plant?||The Royal Horticultural Society's journal, "The Garden" reports that one of Tasmania's endemic plants may be 43,000 years old. A team from the University of Tasmania has found that 78 samples taken from Lomatia tasmanica over its entire range of 1.2 sq km are all genetically identical. A fossil found 8.5 km away and which was morphologically identical to the living species was radio carbon dated to 43600 years old.|
It is postulated that a mutation produced a single plant of L.tasmanica (a sterile triploid clone) which adapted successfully to its environment and spread slowly by underground rhizomes.
|Dubious Benefits||Quandong (Vol 22 No 2 1996) reported that between 1947 and 1985, 463 exotic grasses and legumes in at least 2033 varieties were intentionally introduced into northern Australia. Of these, 21 (5%) came to be recommended as useful plants while 60 (13%) became weeds. Of the useful plants, 17 also became weeds which left 4, or less than 1% as useful and non-weedy. (From the Rainforest Study Group Newsletter, January 1997).|
|Fallen Giant||A massive jarrah tree (Eucalyptus marginata) estimated to be up to 1000 years old was recently felled in a logging operation under the control of the Western Australian Department of Conservation and Land Management (Habitat Australia ; June 1997). A photo accompanying the report showed the tree to have a base diameter of about 3 metres. A spokesman for CALM said "if people had told him the tree meant something to them he would have spared it."|
|Bush Foods||A new magazine on Australian bush foods was launched in March 1997. Australian Bushfoods Magazine aims to cover cultivation, recipes, uses, history, indigenous aspects and marketing of edible Australian species. The editor/publisher, Sammy Ringer is a grower/writer and further information can be obtained from him at 38 Mountain View Rd, Maleny, Queensland, 4552.|
|Short-lived Reign?||In June, the long reign of "The Grandis", a 76 metre tall "Flooded Gum" (Eucalyptus grandis) as New South Wales' tallest tree, was apparently ended when a 79.6 metre Eucalyptus nobilis ("The Noble Tree") was surveyed near Armidale in the state's north west. However, never slow to take up a challenge, foresters in the Bulahdelah area (home of "The Grandis") have now re-surveyed their tree at 84.3 metres. |
The next move is awaited with interest.....
From the Sydney Morning Herald of 10 June 1997 and August 23 1997
Until next time...good growing.
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Australian Plants online - September 1997
The Society for Growing Australian Plants