Dunns Swamp: By the Water

This year for my birthday I convinced my family to take a Friday off work to relive our childhood camping trips to Dunns Swamp (or Gangaddy) in Wollemi National Park. I was in botanical heaven!

Around the campsite alone there are several vegetation types. Dunns Swamp or Ganguddy (the Wiradjuri name) is on the Cudgegong River in Wollemi National Park. The River was dammed in 1920s when Kandos Weir was built to provide water to the Cement Works in Kandos. Shrubs, grasses and sedges grow in the moist, sandy-peaty soil along the waterways. The campsites are set up amongst low woodland on shallow sandy soil. Finally, organic matter fills up little hollows in the large rock formations and little heath communities spring up. This is one of three blog posts about the flora of Dunns Swamp. I will be starting with the plants by the water’s edge.

Acacia filicifolia or Fern-leaved Wattle, is a common species throughout New South Wales. It has the standard fluffy yellow flowers of an Acacia. The feathery looking compound leaves have inspired the species name; filici  comes from the Latin for fern, while folium means leaf … giving us ‘fern-leaved wattle’.

Acacia filicifolia, Dunns Swamp Sept 2017 (Image: C. Simpson-Young)

Acacia filicifolia, Dunns Swamp Sept 2017 (Image: C. Simpson-Young)

Calytrix tetragona or Common Fringe Myrtle have the most beautiful flowers. Once they develop into fruit and fall away they leave their bright red calyx behind. A calyx is the ring of leaf-like structures surrounding a flower. Caly is for the stunning calyx (calyx comes from the Greek for cup) and thrix (hair) for the hair-like calyces.  Tetragona means four angles and refers the leaf shape.

Calytrix tetragona Dunns Swamp Sept 2017 (Image: C. Simpson-Young)

Calytrix tetragona, Dunns Swamp Sept 2017 (Image: C. Simpson-Young)

Eleocharis sphlacelata or Giant Spike Rush grows in deep still water in dense swards, creating large areas of important habitat. It provides shelter and food for insects, birds and fish. Some insects drill through the stem to access the oxygen within the hollow, cylindrical stem. Even algae benefits as the stalks provide a surface to colonise on. The scientific name is a little oxymoronic; Eleocharis means “marsh beauty” while sphacelata means “diseased” referring to the weird looking flowering spike.

Eleocharis sphlacelata, Dunns Swamp Sept 2017 (Image: P. Simpson-Young)

Eleocharis sphlacelata, Dunns Swamp Sept 2017 (Image: P. Simpson-Young)

Exocarpos strictus, Dwarf Cherry or Pale-fruit Ballart is a hemiparasitic shrub that flowers all year round. A hemiparasite gets some of its food through parasitism and some through the standard method of photosynthesis. The Dwarf Cherry sucks nutrients from the roots of other plants with the help of mycorrhizal fungi. The tiny flowers turn into black fruit with swollen red or white stems which are popular with birds. They can grow in all sorts of environments, from heathland to dense woodland.

Exocarpos strictus Dunns Swamp Sept 2017 (Image: C. Simpson-Young)

Exocarpos strictus with tiny yellow flowers. Dunns Swamp Sept 2017 (Image: C. Simpson-Young)

Patersonia sericea, Purple Flag or Native Iris, has grass-like leaves and stunning bright purple petals. The species name ‘sericea’ comes from the latin sericated meaning ‘clothed in silk’, because of the silky hairs at the base of young leaves. As you probably know showy flowers exist to help plants reproduce by attracting critters to help move pollen from one flower to another. The male organ (called a stamen) releases pollen and the female organ (stigma) receives the pollen. You may be able to see in the picture that Patersonia sericea has several stamens that have fused together to make a tube around the stigma.

Patersonia sericea, Dunns Swamp Sep 2017 (Image: C. Simpson-Young)

Patersonia sericea, Dunns Swamp Sep 2017 (Image: C. Simpson-Young)

Psilotum nudum or the Skeleton Fork Fern is a strange plant that doesn’t have the organs that normal plants do. For example, it doesn’t have proper roots, just a stem that grows undergound. This is how it got a Latin name that means ‘bear naked’. Plant life started with organisms like algae and moss. They didn’t have any vessels to move water and nutrients, so they can never stray far from the water or grow tall. The next step in the evolution of plants was to develop vessels for water and nutrient transport, and these primitive plants would have looked a lot like Psilotum nudum.

Psilotum nudum, Dunns Swamp Sept 2017 (Imagge: C. Simpson-Young)

Psilotum nudum, Dunns Swamp Sept 2017 (Imagge: C. Simpson-Young)


Australian National Botanic Gardens, Calytrix tetragona

Australian Native Plant Society Sutherland, Patersonia sericea

Berkeley University, Introduction to Psilotales

Friends of Lane Cove National Park, Patersonia sericea

Mieke M. Kapa & Bruce D. Clarkson (2009) Biological flora of New Zealand 11.
Eleocharis sphacelata, kuta, paopao, bamboo spike sedge, New Zealand Journal of Botany, 47:1,
43-52, <http://www.tandfonline.com/doi/abs/10.1080/00288250909509792>

Nathan Baily, An universal etymological English dictionary, Volume 2

New Zealand Plant Conservation Network, Eleocharis sphacelata

OEH (2016), Ganguddy Visitor Guide.

Understory Network, Exocarpos strictus

Watson, D. McGregor, H., Spooner, P. Hemiparasitic shrubs increase resource availability and multi-trophic diversity of eucalypt forest birds, Functional Ecology, 2009, 150, 889–899 <http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2435.2011.01839.x/pdf>

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