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Petalostigma pubescens Domin 1927
pronounced: pet-al-oh-STIG-muh pew-BESS-kenz
(Picrodendraceae – the quinine family)
common name: Quinine Tree, Bitter Bark, Strychnine Tree
The Picrodendron family is named from the Greek πικρος (pikros), bitter, and δενδρον (dendron), a tree, referring to the bitter taste of many of the fruits. This family was previously included in Euphorbiaceae, but its plants do not contain latex.
Petalostigma is from two Greek words πεταλον (petalon), a leaf, and στιγμα (stigma), a brand, tattoo-mark. Both of these words have, of course, been adopted by botanists as petal and stigma, and the name of the genus probably refers to their current botanical use. The genus was first described by von Mueller in 1857. It has seven species found in New Guinea and Australia.
The Quinine Tree is a tree of eastern Australia, north from the Clarence River, and also in parts of Western Australia and the Northern Territory, found usually in open woodland dominated by eucalypts, and sometimes on coastal sand dunes. It was first described by the Czech botanist Karel Domin (1882–1953) in 1930. There are numbers of this tree growing by the side of the West Point Road.
It is a small tree, growing up to about 5 m in height, and sometimes as high as 10 m. The leaves are ovate to orbicular, 2–6 cm long, 1–2.5 cm wide, the margins entire, the upper surface dark green; the lower surface is grey and finely pubescent with both long and short hairs; the petiole is 3–8 mm long, and hairy. The Quinine Tree is dioecious. The male flowers are in clusters of 3 or 4, the female flowers solitary. The flowers are insignificant, but are followed by fruits up to 2 cm in diameter that are quite prominent. These are 3–4 locular orange-yellow capsules, and explosively dehiscent.
Does this tree actually contain quinine? Some authorities say ‘yes’, and others ‘no’. As far as I can ascertain, quinine occurs naturally only in the bark of the Cinchona tree. For centuries the Peruvian Indians used an infusion of Cinchona bark to treat fevers, and European explorers and settlers soon realized its efficacy in treating malaria, although the alkaloid quinine itself was not isolated until 1820. Quinine is also used as a flavouring, and it provides the bitter taste in tonic water. I understand that ‘gin-and-tonic’ was originally drunk to prevent attacks of malaria†. Gradually, natural quinine has been replaced by chemically synthesized drugs such as chloroquine and mefloquine.
Whether it contains quinine or not, both the bark and the fruits of Petalostigma pubescens have been used traditionally to make a bitter tonic, and to treat fevers, including malaria. A bark infusion has been used as an opium antidote, to relieve sore eyes, and as an antiseptic wash. Fruits held in the mouth were reputed to relieve toothache. Fruits used for medicinal purposes are used fresh, as they apparently lose their activity after drying.
The wood of the tree is very hard, and was used to make spear-throwers.
The source of the ‘Strychnine Tree’ common name is not clear, although I have seen reports of a preparation made from the tree being used to kill fish.
Caterpillars of the Copper Jewel Hypochrysops apelles use this as a food plant.
† or so they say! It sounds like a good excuse to me!
Information about medicinal qualities of plants, or about their use as medicines, is for interest only, and is not intended to be used as a guide for the treatment of medical conditions.
Photographs taken 2010, 2012, West Point Road, 2014 Nelly Bay
Page last updated 14th January 2017