Greetings fellow Foxies,

​Yay it is peak spider time in the bush.
 Recently I was photographing blobs of gum exuding from a manna wattle trunk, when I saw an amazingly well-camouflaged little spider within 15cm of my eye. I initially thought that it was a small false wolf spider, but the two long spinnerets indicate a two-tailed spider (Family Hersiliidae genus Tamopsis).
These little spiders are quite common on tree trunks in Eastern Australia, but I have never seen one and find few records of them in WA.
Two-tailed Spiders are day and night ambush hunters. The spider waits for the prey on a rock or tree trunk. When there is a small insect within range, the spider will face backwards to the insect, then moving side-way like a crab, runs around and around it, enmeshing the insect with thick silk released from its long spinnerets.
When the silk tightens, the spider turns around, bites an opening through the silk and starts feeding.
Two-tailed spiders are absolute masters of disguise that can change colour and pattern to match their surroundings (see the spider below). Check out these amazing images by Farhan Bokhari (Myrmician)
Their egg sacs are tiny silken balls of eggs like the ones below.

​Hello fellow Foxies,
Tiny (1cm) delightful blue Tall Lobelia Lobelia gibbosa flowers are out now. Each single stemmed plant has small, withered leaves on a fleshy stem with one to four pale blue striped flowers that are hard to spot, but is worth the search.
The larger Tufted Lobelia Lobelia rhombifolia (October/November) also has (deep) blue flowers that remind me of a fleur-de-lis. They are hardy annuals that only occur in ones or twos, mostly and sandy spots with little vegetation. I think they would flourish after a fire.

​Lobelias belong to the Campanulaceae family with two other late-spring annuals in Foxes Lair, Isotoma hypercrateriformis and Wahlenbergia gracilenta (rare here) that occur in the claypit area.

​World-wide the Campanulaceae family is known for large and showy flowers, but not in WA.
They share these distinctive features.

• Inferior (under the flower) ovary.
• They exude a nasty sticky white sap when cut.
• Instead of starch they store energy as inulin. Unlike starch, inulin is digested in the colon rather than in the stomach, and is very good for gut health. Before you harvest lobelias for the inulin, note that it may cause gaseous eruptions in the bowel department (a curse on Jerusalem artichokes!), and:-
• Some plants contain toxins. The common name for Isotoma hypercrateriformis is Woodbridge poison.
• Some plants like Lobelia gibbosa and Isotoma hypercrateriformis have fleshy stems that enable flower and seed formation to continue long after the leaves have died.
• Campanulaceae and Asteraceae (sunflower family) have a remarkable stigma and stamen arrangement that is described in the extract below from this web page.

 
Inside the flower, the five stamens are arranged closely together around the central female style and are often fused together, thus forming a little cylinder. When they are mature, the stamens release their pollen into the centre of the tube they form, where the pollen collects. The style will then grow longer, slowly pushing the mass of pollen out of the tube, where it then falls on the backs of bees that visit the flower for nectar. Once all the pollen is pushed out and the female style is mature, the tip will split open to reveal sticky surfaces where it can receive pollen from other flowers. In other words, the flower will not pollinate itself, because the pollen is released and pushed out of the way before it is ready to be pollinated.
After much crawling around on tick-infested ground I managed to photograph this arrangement in Lobelia gibbosa. From the flower base, the tube curves up through a split in the upper petals and down again to end where it will brush the back of insects entering the flower. 

​Upper petals have been removed from the images below to show the fused stamen tube.

​Hello fellow Foxies,
About three years ago during a very dry spring I noticed that parrotbush (Banksia sessilis) plants on Banksia Walk shallow ironstone soil east of the water tank were severely infested with a scale insect. The damage has progressed each year to the extent that most plants there are dead or unthrifty. Accompanying golden dryandra (Banksia nobilis) plants are much less affected

​After much investigation I discovered that symptom severity is linked to soil water holding capacity, with far less damage on deeper and sandier soils. Another finding was that two organisms are involved. The first was identified as whitefly, but a new species rather than the common Aleurotrachelus dryandrae
Adult whiteflies look like tiny white powdery moths, but I am yet to see any. The mains signs are small powdery spots (early larvae), yellowish to brown scale-like mid-stage larvae and pupal cases that look like miniscule white crystal coffins. Whitefly are supposed to only be on the leaf underside, but this species is often on the upper side. Infested leaves often have a powdery or waxy looking coating and black spots that may be associated with honeydew exuded by the larva. The spots look like insect poo to me!

​While the leaves are being sucked dry, the growing points are also being killed by an evil caterpillar. From an egg laid on shoot or flower, the caterpillar hollows out the stem to the first node. It returns to the dead growing point to pupate and exit.

​Moisture stressed plants are more susceptible to diseases and pests, and increased temperatures also increase temperatures worsen pest damage by speeding up their life cycle.
The Banksia walk was named after a small group of Bull Banksia (Banksia grandis) plants that occur on this soil. They have been struggling in recent years, and some are dying this summer. Interestingly they are not greatly infested with whiteflies or borers. This area is a photo-reference site that I have been monitoring. Images changes since the 2009 fire.

​This is another biodiversity loss in Foxes Lair in addition to flooded gum death, marri decline, and wandoo crown decline that I have observed in the last 20 years.  I still remember being surprised when I arrived in Narrogin in 1986 and a farmer told me how much his farm’s rainfall had fallen. We now have even less and more variable winter rainfall. 

​Greetings fellow Foxies,
I recently went for a holiday to a suburb of Narrogin called Augusta. Although a trifle too wet for me, it is a pleasant town and a great spot for the amateur geologist.
​
I explored Groper Bay. This is a delightful spot for a ramble, and the rocks are wonderful!
One must walk from the car park and scramble down rough tracks and rocks (see my journey on image). Note there are no trails, and the rocks are smooth. It is a good workout for a healthy 74-year-old, but not for the dodgy hip brigade
The bedrock once granite and dolerite like Narrogin has been altered and stretched. A north-south trend in rocks is evident on the aerial photo with lines of rock projecting into the ocean. 

The rocks resemble pieces of rock art due to weathering and smoothing by sand and water.
The lumpy stretched rock patterns below are called boudinage.Boudin is apparently French for their black pudding, which is made into sausages!
These rocks have been subjected to a lot of heat and pressure!
In the image below the large grained whiter and fine-grained darker rocks have remained more solid while the more plastic pinkish rock flowed past, but they were stretched and deformed into cylinder cross section rocks called boudins.

​The very picturesque cove (site 3) contains rounded boulders that vary in colour and texture from dark near the waterline, to salt bleached, then bright yellow lichen speckled adjoining the bush. It is a lovely spot but a bit lumpy for sunbathing. In spots what looks like fossilised white scum is draped over rock adjoining the soil line. This is Tamala limestone that outcrops at our beaches. Most limestone has formed in deep ocean from carbonate shell deposits, but this is different. Tamala limestone originated as coastal shell sand dunes. Mild acid from carbon dioxide and water in rainfall dissolved the shell lime and carried it to the base of the dunes where it formed a solid carbonate layer. This has been exposed by wind or wave action that removed the overlying sand. Tamala limestone is a miserable deposit compared to huge depths of limestone elsewhere. It is used for agricultural lime and building blocks and contains the caves. 

​Dark rock forming the western point was a dolerite or gabbro intrusion that has been stretched and deformed into a rock called amphibolite. At the marina fresh amphibolite is exposed at a huge rock face where the side of the hill was blown away to produce rocks for the breakwater.

​The rocks spurred me on to research their origin. Here is a simplified version of my findings.

While Narrogin is on the ancient Yilgarn craton, the capes are on a much younger rock called the Leeuwin-Naturaliste Ridge on the Pinjarra Orogen, which is west of the Darling Fault. (see this blog).
The Leeuwin-Naturaliste rocks formed as granites and mafic rock plutons intruded into a rift that formed on the Pinjarra orogen about eleven hundred million years ago. At this time Western Australia was separating from an unknown continent to the west as the Pangaea supercontinent broke apart.
​
 About seven hundred and fifty million years ago while continents amalgamated again to form the Gondwana supercontinent, India obliquely collided with WA in what is a southwest direction today (Leeuwin orogeny). The collision buried the rocks where they partially melted, and the minerals were altered and stretched into roughly north-south bands (that are sometimes folded) as India also moved south. A substantial mountain range formed at the join and gradually eroded away.

About four hundred million years ago, starting from the north, India gradually began separating from WA. This caused a rift valley to form between the Dunsborough and Darling scarps that gradually filled with sediments from both sides. Today, this is the belt of sandy scrubby woodland between Bridgetown/Nannup and the Leeuwin-Naturaliste Ridge jarrah/karri forests. (Donnybrook Sunkland).
Finally, about eighty-three million years ago, Antarctica finally separated from Australia, taking the southern part of the Leeuwin-Naturaliste ridge, which is now under the Denman Glacier.

When you sip wine at the capes, pause and remember the tumultuous origin of the land you are standing on. Did the ground move or have you had enough to drink?

​Click here for a Google Photos tour of Groper Bay.