Old man banksia tree – wadanggari

What is an old man banksia tree?

The old man banksia is a common woody tree species found along the east coast of Australia. In Darug language banksia is  wadanggari.

Old man banksias are named after their distinctive wrinkly grey bark. Their bark, gnarled and twisted shape and shiny dark green leaves with saw-toothed edges make them easy to identify.

During the flowering season in summer to early autumn, old man banksias feature cylindrical, pale grey-green coloured flower spikes. These spikes are large, ranging from 9 to 12 centimetres wide and 7 to 15 centimetres long. As these flowers age the flower spikes dry and turn a grey-brown. When pollinated, the flower spikes develop into large brown-grey woody seed pods called follicles.

The scientific name of the old man banksia is  Banksia serrata.  Banksia  commemorates Sir Joseph Banks, the botanist who travelled with James Cook on his first Pacific voyage.  Serrata  is the Latin word for saw-edged, referring to the saw-toothed leaves of the old man banksia. Other names for the old man banksia are 'saw banksia' and 'saw-toothed banksia'.

The distinctive saw-toothed edges of old man banksia leaves and conical flowers.

Where are old man banksias found?

Old man banksias grow in well-drained sandy soils. They are often found near the coast, growing at the back of the sand dunes.

In Sydney, old man banksias are also found further inland growing in eucalypt forests and woodlands.

Old man banksias are common in Sydney bushland such as this one arching over the track in the Field of Mars Reserve.

How are old man banksia trees used by Aboriginal Peoples?

Fresh banksia flowers are nectar-rich and can be sucked or dipped in a coolamon of water to make a sweet drink. Smouldering banksia cones can be carried on a lined coolamon to transport fire between places.

What eats old man banksia trees?

The flowers of the old man banksia attract many native nectar-feeding bird species such as honeyeaters and wattlebirds.  Mammals such as  flying foxes,  possums  and gliders have also been seen feeding on the flowers. Invertebrates also feed on the nectar rich flowers.

Yellow-tailed black cockatoos  feed on the immature seed pods that form just after the flowering season.

Yellow-tailed black cockatoo

What adaptations do old man banksia trees have?

Old man banksias are well adapted to dry conditions and poor soils. They have special roots that are efficient at absorbing the few nutrients that are available in the soil. Their leaves are hard and woody which minimises water loss.

Their hard, woody leaves are also difficult for herbivores to eat and digest. Being an unappealing food source means that the old man banksia does not have to waste nutrients or water on replacing eaten leaves.

The tough serrated leaves of the old man banksia.

Like other species of banksia, old man banksias are well adapted to fire. The thick woody trunk protects the interior from heat damage. After fire, leaves resprout from special ‘back up’ buds called epicormic buds found beneath the bark of the trunk.

The old man banksia is so well adapted to fire that its life cycle relies on it. Fire opens the woody seed follicles releasing seeds which are carried by wind to be distributed to the ash bed where they germinate.

After fire old man banksias regrow from epicormic buds

How do old man banksia trees reproduce and what is their life cycle?

Old man banksias rely on pollinators for their reproduction. Native animals such as bees, birds and small mammals such as sugar gliders, possums and bush rats help transfer pollen between the flowers of different trees.

When the banksia flowers are pollinated they form woody seed pods called follicles.

The follicles use fire as a cue to release their seeds. During a bushfire the seed follicles open and the seeds fall and are blown to the ground. The seeds germinate in ash-rich soil clear from other plants which would otherwise compete for sunlight and water.

Because of the relationship between fire and seed release it is important to prevent bush fires from becoming too frequent so that the new seedlings have an opportunity to grow into adults and produce seeds of their own.

In the absence of fire the follicles can also release seeds to the ground when they become very dry or when other parts of the tree are under stress or dying.

Unopened seed pods of the old man banksia

Open seed follicles of an old man banksia cone

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