Pacsoa at 13:16, 29 September 2024

2024-09-29T13:16:12Z

← Older revision		Revision as of 13:16, 29 September 2024
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	senior botanist in the Northern Territory, it is known that		senior botanist in the Northern Territory, it is known that
	many other species do exist in Australia.		many other species do exist in Australia.
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	=== Evolution: ===		=== Evolution: ===
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	indigenous to Australia. It is found much farther afield in		indigenous to Australia. It is found much farther afield in
	Florida, Central and South America.		Florida, Central and South America.
	~~</div>~~
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	===Contributed by: ===		===Contributed by: ===
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	<p>		<p>
	[[Category:Cycas\|OzIntro]]		[[Category:Cycas\|OzIntro]]
	[[Category:Cycad\|Cycas_OzIntro]]		[[Category:Cycad\|Cycas_OzIntro]]

Pacsoa: 1 revision imported

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P>Pacsoa at 21:40, 23 September 2024

2024-09-23T21:40:09Z

New page

{{PalmSpeciesHeader}}
__NOTOC__
<div class="row">
<div class="small-0 large-5 columns">
[[File:Cycas_cairnsianaM.jpg|frame|Figure 1. ''C. cairnsiana'' in habitat, Petford.]]
</div>
<div class="small-0 large-7 columns">
=== Introduction: ===
Many species of the genus ''Cycas'' (pronounced sigh-cas),
the solitary member within the family cycadaceae (pronounced
sigh-cad-ace-ee-ay), have now been recognized in Australia
where once it was thought that only ''Cycas media''
flourished. Two other species were mentioned in early papers:
''Cycas cairnsiana'' and ''C. normanbyana''. No real
clarification existed. Since then, owing to work done by a
senior botanist in the Northern Territory, it is known that
many other species do exist in Australia.

=== Evolution: ===
The genus ''Cycas'' has such pronounced primitive
features that early botanists theorized that it was the
missing link connecting the pteridosperms
or cycadofilicales of the Devonian Era with Zamiaceae
fossils which occured in the Mesozoic age, a much later
period. Even though the genus has very primitive features,
(for example central fronds rising circinately from the apex
and the female not formimg a cone) Dr. L.A.S. Johnson stated
that the genus could hardly have risen from a period before
the Zamiaceae since the genus distinguishing single vein stem
in the pinnae could not have given rise to the frond
condition of living zamiads. Another remarkable thing about
condition of the seed arrangement of ''Cycas'' is that the
seeds form on the margins of a brown-furred, frondlike
megasporophyll issuing from the crown of the trunk and in the
Australian species hanging pendant between the bases of the
fronds. This last feature is definitely similar to what we
know of the pteridosperms of the Paleozoic age. Perhaps
''Cycas'' can be classified as the most primitive genus
alive today. From illustrations given by Professor
Chamberlain in 1919, the primitive seed ferns were also very
similar to this.

===Distribution: ===
''Cycas'' is a far-flung genus of plants occur ring in
Japan, China, Philippines, Taiwan, the Indian sub-continent,
Sri Lanka, South East Asia, Madagascar, Malesia, New Guinea,
the western Pacific and northern and north-eastern Australia.
However, from incomplete botanical study it appears that
Australia has more species than any other country.

===Present Status: ===
Botanical study of Cycadaceae is still in
progress here in Australia and although incomplete, the
amount of progress so far is remarkable when one considers
that very few botanists are studying the entire Cycadale
group with any thought in mind of merit to the plants.
Rather, study is being carried out to determine the
peculiarities of the toxins the cycads contain, and their
effects on primary livestock.

After
discussion with farmers, in particular the man who grazes
cattle, it emerges that most of the Zamiaceae are
inaccessible to stock at normal times. Most zamiads are
either too formidable in leaf structure, or their seed is
enclosed in heavy cones. Also many of them have protective
spines while in cone formation.

However the Cycadaceae present a different picture because
of the peculiar manner of their seed hanging exposed from
between the leaf fronds at the apex of the plant's trunk.
Also in the case of ''Cycas'' the group of tender young new
fronds emerge from time to time in their circinate fashion.
This presents an attractive soft repast to wandering
'scrubbers' or straying cattle who immediately eat this and
develop a ricketts type of complaint or partial paralysis of
the hind legs. Because they are straying stock they die of
starvation rather than from the plant's toxic properties.
I have discussed the situation regarding stock with many
farmers and even those that totally disregard the plants as
having any use will admit that most stock fatalities occur
when drought conditions prevail and fires have burnt off an
area leaving only blackened caudices, which triggers new
growth.

However because of such stock losses reports to primary
industry authorities are made, which result in certain
Australian authorities declaring the indigenous family as
noxious.

Most other countries throughout the world realize their real
value as marvellous botanical specimens with good commercial
possibilities. South Africa and America have raised
protective laws by declaring their cycads as plants in danger
of extinction. Further, could I pose the question, "just how
many indigenous plants have been declared noxious weeds in
their own country?." Professor Chamberlain stated in 1919,
with reference to Cycads, "it is nothing short of vandalism
to destroy by arsenic poisoning, plants of scientific importance."
On the home garden and landscaping front, the extreme
hardiness and palmlike beauty of the cycad family makes them
ideal subjects for tub culture or for planned garden
landscaping. As greater knowledge of the family is gained the
existing law may change to the benefit of all concerned. To
illustrate the degree of lack of knowledge of these plants at
authoritarian level, the reference to the noxious plant by
authorities is as "Zamia", a genus which is not even
indigenous to Australia. It is found much farther afield in
Florida, Central and South America.
</div>
</div>

===Contributed by: ===
L. P. Butt from '''''Palms & Cycads''''' No. 27, April-June 1990.

===External Links:===
<p>[https://www.google.com/search?q=%22Cycas+OzIntro%22&num=10&sa=Google+Search Google],
[https://images.google.com/images?q=%22Cycas+OzIntro%22&hl=en&btnG=Google+Search GoogleImages],
[https://www.flickr.com/search/?q=Cycas+OzIntro Flickr],
<p>
[[Category:Cycas|OzIntro]]
[[Category:Cycad|Cycas_OzIntro]]

Cycas OzIntro - Revision history

Pacsoa at 13:16, 29 September 2024

Pacsoa: 1 revision imported

P>Pacsoa at 21:40, 23 September 2024