Category: Nature

Pink Ash – Alphitonia petriei

 Around the world there are 20 species of this distinctive tree, mostly in tropical Asia, while in Australia there are seven or eight species, found in eastern  northern Australia.  Alphitonias are known by several popular names which can cause some confusion in identifying a particular species. Pink Almond, White-leaf, White Ash, Soap Tree, Sarsaparilla, Red Ash, Red Almond, Foam-bark and Pink Ash are those names most commonly used.

Alphitonia petriei is a pioneer species which grows rapidly on the edge of the forest or in a gap where sunlight can reach.  Trees can grow to a height of 40 meters and sometimes look grotesque with gnarled and twisted limbs and branches which reach out impossible distances laterally from the trunk.  At present trees around Paluma are particularly eye-catching as most are densely covered in white flowers, often with a tiered effect and, from a distance, appear like snow-laden Christmas trees.

The flowers which grow in dense panicles at the ends of branchlets and between leaves are white, cream or pale green. They have five petals, only 1.5 mm long which envelop the stamens. Flowering is usually from September through to March. Pollination is by beetles. Butterflies are also attracted to Alphitonia. The fruit is produced from February to July; globular, dark capsules, which ripen to reveal three orange to red seeds surrounded by a powdery flesh.  Many birds, including King Parrots and Crimson Rosellas, feast on these while fallen fruit is eaten by cassowaries.

Leaves of the Alphitonia are simple, lanceolate and can be 65 to 180 mm long.  The upper surface is glabrous and a dull grey-green in colour while the undersurface is whitish and slightly hairy.  In some species of Alphitonia, notably A. excelsa, the leaves when rubbed in water will produce a soapy froth, hence the popular name Soap Tree.   This species is more commonly found at a lower altitude than that of Paluma.

The bark on the trunk and limbs of this tree is grey, flaky, almost tessellated and if torn gives off a liniment-like odour.  This is a distinctive feature of the tree.  The strong liniment smell of broken twigs and leaves is methyl salicylate, produced in the cambial layers of the limbs.  Some people liken the smell to sarsaparilla, hence another popular name for this tree.  Rainforest Aborigines used the Alphitonia petriei medicinally, probably as a liniment.

Alphitonia petriei is one of the many rainforest trees that contain bio-active chemicals which could potentially produce valuable medicinal drugs.  In his book ‘Plants of Tropical North Queensland’, John Beasley says that “research at Paluma found that more than half the trees tested showed marked bioactivity.”

There are many of these interesting trees growing in and around Paluma.  Particularly good specimens may be seen outside No 62 Mount Spec Road and at the corner of the western entry to Lennox Crescent from Mount Spec Road.

Text and photos by Colwyn Campbell

Tropical Bleeding Heart     Homolanthus novoguineensis

It is hard to ignore this attractive, graceful tree which is also known as Native Poplar. Its leaves are simple with a smooth, glossy upper surface and glaucous (pale bloom) underside. The stems exude a milky sap when broken. But the striking feature of this tree is the scattering of brilliant red and orange leaves among the heart-shaped green leaves. Leaves can be quite big, up to 14 cm long and 12 cm at their widest breadth and as they age, rather than a mass seasonal colouration change, a few at a time turn bright red before dropping.

The leaves actually do not turn red. As the leaf ages it ceases photosynthesizing, the green chlorophyll is taken back into the tree as stored energy. Gradually the green pigment is reduced, leaving the brilliant red and orange colouration seen in expended and dropped leaves.

The tiny flowers occur in clusters in leaf axils. They are white or cream, have no petals and are only 1 to 2 mm diameter so are often difficult to detect. Flowering can occur in any month. The fruits which follow are small green to purplish capsules about 8 to 10 mm in size which contain 2 brown seeds enclosed in yellow or orange arils. The fruit is eaten by many bird species, notably Rifle-birds, Bower-birds and Pigeons. Possums eat the leaves.

The Bleeding Heart is also the host tree for the Hercules Moth which is the largest moth in the World.

Bleeding Heart trees grow over a large area of rainforests, swamp forests and sclerophyll forests in North Queensland, NT, WA, Solomon Islands and New Guinea. They are fast growing and can grow to a height of 25 meters when buttresses may form. The tree is a forest pioneer, one of the first to re-establish after a disturbance or devastation such as a cyclone. Its presence provides shelter for other rainforest species to germinate and become established.

As you take a stroll through the village, you will see many of these trees, from seedlings only a few centimeters high to slender trees of 3 or 4 meters.  After cyclone Yassi in  2011, a large number of seedlings sprung up in newly open areas around some village gardens.  A good example of the tree can be seen along the McClelland’s Lookout path.

Closely related is Native Bleeding Heart, Homolanthus nutans, also known as Native Poplar. This remains usually as a shrub or small tree, growing to about 8 meters. In every other respect, including distribution, it is very similar to the Tropical Bleeding Heart.

For more information, see: Plants of Tropical North Queensland: John Beasley

Text and Photos by Colwyn Campbell

Gympi Gympi (Dendrocnide moroides)

 The Gympi Gympi is also known as the Stinging Tree, and is said to be one of the world’s most venomous plants.  Those unlucky enough to have suffered a major sting claim the pain is the most excruciating of any they have endured.

World-wide there are 37 species of stinging tree with 6 in Australia.  The Dendrocnide moroides has the worst sting. The tree is often described as a shrub but can grow to a height of 4 to 5 meters.  It tends to grow in open, disturbed sites such as a cyclone damaged area or in a clearing where a tree has fallen.  They like sunny, but sheltered areas and are often found along walking tracks or the edges of streams.  The Gympi Gympi is found from Gympie in Southern Queensland to Cape York Peninsular and is very common in the Atherton Tablelands.  It is generally not common along any of the Paluma walking tracks that have a complete rainforest canopy, but small plants can spring up quite rapidly in damaged areas exposed to sunlight.

The leaves of the Gympi Gympi, carried on long, hairy stalks are finely serrated and heart-shaped.  They are covered in fine stinging hairs which give the leaves a furry appearance. The fine silica hairs break off when touched and embed in the skin.  They act like syringes and continue to inject venom for several days. Even dead leaves are capable of inflicting a sting.  The pain experience depends on the amount of contact with the leaves but also varies between people. A brief brush with a leaf can lead to significant but bearable localized (surface) pain, but extensive contact (especially in sensitive areas of thin skin) can be excruciating, often with extreme reactions like swelling and profuse sweating. The pain reduces over time but can linger for over a month.  Rubbing the skin exacerbates the situation as it breaks the hairs, leaving the points embedded in the skin. Also, contact with cool water leads to recurrence of pain days or weeks after the event. Unfortunately for those stung, there is no truly effective treatment although shaving the affected area and then daubing it with a weak solution of hydrochloric acid or  full strength house-hold vinegar can help to alleviate the worst of the pain. This treatment is only for the strong-minded since it causes the pain to significantly increase for several minutes before acting to reduce it.

The chemicals contained in the venom are not completely understood but it is suggested that a peptide called moroidin could be responsible for the pain.  Some birds, mammals and insects appear to be immune to the venom as many eat the fruit and leaves without harm.  The fruit is edible to humans brave enough to sample them and are quite pleasant in flavor – just be careful not to touch the leaves or stem when picking the berries!

The fruit of the Gympi Gympi is actually a small nut enclosed within a fleshy sac.  Several sacs are clustered together to form a mulberry-like fruit which hangs from a stem.  The stems and fruit are also covered in fine hair.