Plants are Amazing- Series Two

Well I hope you have all been admiring the many amazing adaptations that plants have developed to cope with the harsh Australian climate in your gardens or while bushwalking, and have possibly noticed a few more structural features that plants have and maybe questioned the reasons why they have these features. Detailed below are some more amazing features that you may have noticed along your tracks.

As you walk around the garden or along your bushwalks you will see numerous examples of leaf adaptations designed to cope with low rainfall, searing summer temperatures, or saline soils. Examples of leaf adaptations include short, leathery leaves which have reduced surface area to minimise evapotranspiration (water loss due to evaporation). Other examples are terete (tubular leaves), spiky or in rolled leaves. Look at the leaf structure of Spinifex plants. Wattles have phyllodes (modified stem structures) instead of true leaves- this is believed to be a response to our infertile soils, rather than to the dry, hot climatic conditions.

Some heat defecting modifications of leaves include the presence of stellate (star-shaped) or branched hairs, scaly or waxy cuticles (outer surface of leaves), and the blue-grey colouration of many plants. Many of the Emu Bushes have hairy stems or leaves, and many of them are also blue-grey coloured. Saltbushes are well represented in arid regions in Australia, and many of these have scaly or hairy foliage, as well as succulent leaves (water-storage), and vesicle structures on their leaves to assist with salt exclusion for survival in saline soils.

Another leaf modification some plants have to limit evapotranspiration is the placement of stomata (the structure where gas exchange occurs) - some plants limit these to the underside of leaves, while others have their stomata hidden in pit-like structures, often covered by fine hairs.


The orientation of leaves in plants is often with the leaf edge turned toward the sun in order to reduce the surface area impacted on by evaportranspiration. Look for this feature in some wattle species.

Stem modifications are also apparent in some plant species to help them survive the harsh climate. Mallees are multi-stemmed gum trees (Eucalyptus species) that have modified stem base called a lignotuber which allows the trees to sprout again after severe drought or fire has killed off the top growth. Multiple growth points under the bark of trunks of many Eucalypt species allow them to re-sprout along their trunks after fires.

Stay tuned over the next fortnight for more amazing plant adaptations.

Imaged sourced from Botanical Gardens at the University of California, Los Angeles (UCLA)

Penrith Walks Against Warming

After a week or so of overcast, cool and showery days it was a minor miracle that Sunday 11 November dawned as a mostly sunny and fine day - just perfect for the Penrith Walk Against Warming.

More than 100 people turned up to Weir Reserve in Penrith to lend their support to the walk, which aims to increase awareness of the issue of climate change and global warming among all levels of the community.

Just after 10am the crowd gathered for a couple of short speeches - one from Councillor Karen McKeown, who is Penrith City Council's Sustainability Champion, and another from a concerned local resident, Nevin Sweeney. Following these words the group headed off for a march along the Great River Walk.

It was a leisurely stroll alongside the beautiful Nepean River with most people stopping to pick up a temporary tattoo to mark the day!

After getting back to Weir Reserve there was plenty of time (and space) to relax with a sausage sandwich and cold drink thanks to the Penrith Lions Club and to pick up a free native tree to take home and plant in the garden.

All in all it was a great day that I'm sure will be bigger and better in 2008!

Penrith Walk Against Warming

Penrith City Council is supporting a local ‘Walk Against Warming’ right here in Penrith on Sunday 11 November to raise awareness of the urgent issue of climate change.

Come along and show your support by walking with us for a short way along the Great River Walk. Meet near the rotunda in Weir Reserve (off the Great Western Highway) at 10am and if you are one of the first 100 to arrive you can also pick up a free sausage sizzle and native plant!

We need your help to get the message out there so if you would like some posters (A4 or A3) or postcards to distribute at your school, church or in your neighbourhood contact Carmel Hamilton on 02 4732 8050.

If you have your own printer at home or would like to email the posters or flyers to your friends and relatives you can download the A4 poster, the A3 poster or a single postcard flyer.

Hope to see you there!