Tropical Topics An interpretive newsletter for the tourism industry

Woodlands of the lands No. 71 December 2001 Conserving moisture Notes from the Life is tough for living in the seasonally dry tropics. Soils arepoorandforhalftheyearthelandisparchedandproneto Editor fireswhilefortheotherhalfitisinundatedwithwater.Only Millions of years ago, much of the plantswhichhavebeenabletoadapttothispunishingregime Australian continent was covered cangrowhere,havingdevelopedcertaincharacteristicsto with rainforest. However, as the makethispossible. climate changed and the continent became more arid, a new type of While trees in the rainforest tend to It seems that these evolved consisting of have spreading surface roots to make trees are simply using plants which adapted themselves the most of nutrients available on the different survival to the new harsh conditions – floor, those in savanna lands strategies. It is as if they notably eucalypts, acacias, generally have deep root systems, to make the choice between melaleucas, grevilleas and reach deep reserves of water. Some investing energy into producing a . trees concentrate their resources in the strong, long-lasting product or early stages of growth on developing numerous poor-quality disposable These types of trees now occupy a deep and massive tap root. ones. Studies have shown that the much of the savanna lands. This ‘construction costs’ to a tree for Tropical Topics cannot, of course, Once obtained, water must be used production of deciduous are describe them all but looks at economically. The thick bark on many lower than the costs of producing strategies for living in an tropical trees, apart from evergreen leaves. inhospitable environment, giving protection from fire, can help to characteristics of the main groups conserve moisture. Leaves, however, Evergreen leaves need more built-in and at some individual species are a major ‘leak’ due to transpiration – defences, such as a tough structure or which may be particularly common the evaporation of water through the toxins, to prevent damage from - or have interesting features. A leaf pores (stomata). To minimise water eating animals over their relatively number of books, which are loss, the leaves of many tropical long life-span. These attributes are dedicated to identification of woodland trees have a leathery largely lacking in the disposable individual species, are listed in the texture, with a tough, thick, surface cell deciduous leaves. On the other hand, Bookshelf on page 8. layer and are sometimes hairy or deciduous leaves photosynthesise woolly. The stomata are often sunken more efficiently because they contain Acknowledgements below the surface. Leaves tend to more nitrogen and are usually larger IwouldliketothankJohnClarkson, hang down at angles, thus minimising than evergreen leaves. The extra Eda Addicott and Ian Fox of the exposure to the sun and encouraging nitrogen makes them more attractive to QueenslandHerbarium(Mareeba) convectional cooling. The grey-green leaf-eaters, but allows them to ‘feed’ for their help with this issue. colouring or pale undersides of some more energy into the to leaves also helps to reflect heat away. compensate for their short working Please note life. Evergreen leaves, conversely, thatyouarewelcometophotocopy Grasses and many other small plants repay the tree’s investment by Tropical Topics. However, if the simply disappear during the Dry, some photosynthesising, textisreproducedseparatelyitmust dying after setting and others albeitmoreslowly, not be altered and must persisting underground as dormant for a full 12 acknowledge the Environmental roots and tubers. It is fairly common months a Protection Agency as the source. for trees to also shed their leaves and year. Illustrations must not be reused ‘play dead’. However, not all trees take separately without permission. this option – deciduous (leaf- Please contact the editor (details shedding), semi-deciduous and on the back page) if in doubt. evergreen trees co-exist throughout the savanna . Kapok trees are deciduous

1 The big three Eucalypts,melaleucasandacaciasdominatethedrytropicalwoodlands.Thefirsttwoareparticularlycommoninareas wherethereisareliableannualwetseason,eucalyptsfavouringthedriersituationsandmelaleucaspreferringthose whichareseasonallyflooded.Acaciaspredominatefurthersouth,inaridareaswheredroughtmaylastforyears. Ubiquitous eucalypts Eucalypt trees are synonymous with – although a number of species also grow on islands to the north where theywouldhavespreadattimesoflowersealevels. Separatedeucalypts Buds In 1995 all the bloodwoods were separated from the The name Eucalyptus comes from two Greek Eucalyptus genus into their own genus, Corymbia. There words – eu, which means ‘well’ and kalyptus are now 550 recognised Eucalyptus species and 130 which means ‘covered’. This is a reference to species of Corymbia. Bloodwoods are better represented the unusual flower buds which are covered with a little in northern Australia than in the south. They are present, cap (or operculum) which is actually formed from the and sometimes dominant, in the northern eucalypt fused petals and . When the cap comes woodlands. off, the numerous unfurl around the central pistil, or female part – eucalypt flowers Bark have no petals as such. Eucalyptsarecommonlyreferredtoasgum trees, but these trees with typically smooth Gumnuts barks are only part of the story. Other Eucalypt fruits are also distinctive. After fertilisation, the eucalypts have quite different barks. cup-like base of the flower dries, enlarges and becomes a woody fruit – the gum nut. The roof of the ovary splits, in In gum trees, the bark, or outer, dead layer of most species, into hard woody valves – which tissue is shed annually, exposing the new, might poke out in the form of points, or may sink innerbarkbelow.Thisisoftenhighlycoloured below the rim, out of sight. The various shapes and may be covered with a white powder. In of these gum nuts, along with size and shape of some species, old bark remains attached in dangling strips. the buds, can help with identification. Rough-barked species, by contrast, retain the outer dead bark allowing it to accumulate year after year. As the girth of the Commoneucalypts trunk increases, this bark splits longitudinally. The different Stringybarks (Eucalyptus tetrodonta) and woollybutt (E. patterns created depend on the varying nature and lengths of miniata) are the most widespread tree species in northern the fibres composing the bark. tropical woodlands, occurring over Cape York Peninsula, the Top End and the Kimberley. Stringybarks (right) have a thick, spongy, fibrous bark which can be pulled off in long strips. Although Eucalyptus tetrodonta (left) is often called the Darwin stringybark it is Ironbarks have a solid, thick, common right across northern Australia. heavybarkwithdeeplongitudinalfurrows. Woodlands dominated by this species It is often impregnated with sap (gum) cover almost 37 percent of Cape York fromthetree,knownaskino,whichmakes Peninsula. It can form dense patches. itveryhard.Itisgenerallyverydark–grey orblack. The stringybark has a long tap root and does best in deep, sandy soils. It can grow to 30m, but its Bloodwood (Corymbia sp) bark is often height depends on the depth of the soil. The name tessellated, or chequered. This is because the tetrodonta is composed of the Greek words tetra short fibres in the bark break into small plates (four) and odontos (teeth) refers to the four which may be hard and woody, spongy or loose prominent projections below the cap of the bud and flaky. The trunk may be patterned with which later form four ‘teeth’ on the capsule. differentcolouredplates.Ablood-redsap(kino) leaks from wounds in the bark. Darwinwoollybutt (E. miniata) also Box eucalypts have a firm short-fibred bark with narrow growswell longitudinal lines or tessellations. It is relatively thin and may beyond the Northern wear off, leaving a mottled appearance. These trees are named Territory and is commonly after the European box trees due to the similar pattern of found associated with E. interlocking grains in the timber. tetrodonta right across the northern woodlands. Growingtoabout15-25m, Deciduouseucalypts this tree has earned its Although they are known as evergreen trees, in northern common name from the Australia a number of eucalypt species respond to the particularly spongy and fibrous seasonally dry conditions by dropping their leaves. This bark which grows a quarter to half-way is unusual in eucalypts. However, it enables certain up the trunk. Above this, the bark is smooth and white. eucalypt species to compete effectively in shallow soils. Flowers are a stunning orange with bright yellow-tipped On deeper soils evergreen species dominate. stamens and are responsible for the scientific name: miniatus is the Latin word for ‘flame’. The barrel-shaped, The degree to which a tree loses its leaves may be related ribbed gum nuts, grow to 6cm in length and almost as wide. to the situation in which it grows. For instance, poplar They are popular in flower arrangements. Native bees often gum (E. platyphylla), found in eastern , may nest in branches which have been hollowed out by termites, drop all its leaves in a dry situation but just some of them providing ‘sugarbag’ – a traditional source of honey. in a well-watered position.

2 Melaleucas Melaleucassometimesgrowalongsideeucalypts,buttheytendtodominateinareaswhicheucalyptsavoid–low- lying areas which are flooded in the wet season. Most species of melaleucas need some moisture below the surface soareoftentobefoundwhereaclaysubsoilexistsbelowasandysurface;areaswheremelaleucasgrowshould generallybeavoidedbydriverswhodonotwishtobecomebogged.Areasdominatedbyeucalyptsarebetterdrained andoftensandy.

Some melaleucas, such as Melaleuca quinquenervia harmful compound, cineole, in many melaleuca oils limits thrive in swampy areas where they grow, along with them to external use. pandanus, in almost permanent water. However, other melaleucas are more at home in drier areas which are Thebroad-leavedpaperbark(Melaleuca flooded only in the wet season. The thickly layered, viridiflora) occurs across northern papery bark protects the trees from moisture loss and Australia. Depending on conditions, it may from fire. Interestingly the name ‘melaleuca’ is derived be a small straggly shrub or a straight- from the Greek words melanos, meaning ‘black’, and trunked tree up to 18m tall. It is very leucos, meaning ‘white’. The first specimens described by adaptable, growing on steep mountain Europeans had probably been recently burnt and the white slopes on the edge of the Wet Tropics branches were contrasted against a black trunk. Paperbark is right through to swamps and coastal plains a commonly used name but the name ‘teatree’ refers to both and most areas between. It can be a scattered shrub in a melaleucas and to members of the Leptospermum genus. woodland, or a dominant species in . The bark of melaleucas has traditionally been put to many This tree has the largest and coarsest leaves and the largest uses by indigenous people, notably as roofing material for flowers (stamens 2cm long) of all melaleucas. It flowers shelters. The aromatic leaves yield essential oils with heavily with cream to yellowish-green ‘bottlebrush’ flowers germicidal properties. M. cajuputi is the source of cajuput (viridiflora means ‘green flowers’) which attract bees, oil which has many useful properties, notably as a powerful butterflies, birds and flying foxes. The flowers are anti-spasmodic stimulant. However, the presence of a occasionally red.

Acacias Acacias, also known as wattles, belong to the largest genus of flowering plants in Australia.Oneofthemostwidespreadplantgroups,theycanbefoundgrowingin well-drainedrainforestconditionsbuttheirmainstrongholdistheverydriestparts oftheAustraliancontinentwhererainfallisinadequateforeucalypts.Throughoutthe savannawoodlands,acaciasmaybefoundasanunderstoreyoronshallow,gravelyor sandysoilswhichareunsuitableforthemoredominanteucalyptsandmelaleucas. Theysometimesformquitelargecommunities. Acacias are well adapted to drought, poor soils and fire. In that they often germinate at the extremely dry times, acacias simply stop growing, and wait best times – when fire has for rain. When it falls, water is produced a nutrient-rich ash bed. directed by the branches towards Acacia flowers are tiny but cluster the base of the trunk. together in ball-shaped or elongated Most species, as adults have no groups. Their colour varies from cream leaves. They start life with small to gold. One acacia species (A. fern-like leaves (right) but as the purpureipetala), west of Herberton in little seedlings mature the leaf- Queensland, has purple flowers. stalks to which they are attached become enlarged AustralianversusAfricanacacias and flattened. They outgrow Acacias are found in all continents except Europe and the little leaves which eventually drop off. For the rest of its Antarctica. They are particularly widespread in Africa – life, the plant will rely on these tough, flattened leaf stalks, but close examination shows that these plants are very called phyllodes, to perform as leaves. The advantage is different, having evolved survival strategies which best that they lose less water than normal leaves. suit conditions in their respective homelands. Phyllodes generally have several main veins, running • Few Australian acacias have leaves. The phyllodes are parallel to the edge, but no midrib vein. Tough, low in food unattractive to herbivores. African acacias all have value and containing unpalatable chemicals, they are leaves, which seem designed for browsing herbivores. unattractive to leaf-eating animals. At the base of each (The spines on African acacias are designed to protect phyllode is a small gland which often produces the developing leaf buds, not the leaves themselves, nectar. This attracts ants, which act as an extra which fall to the ground if not eaten.) deterrent to herbivorous insects. • Australian acacia seeds are sown by ants and birds, attracted by the elaiosome (not by the dry cast-off Acacias are legumes, so they have pods); in Africa, large mammals distribute their seeds nodules in their roots containing after feeding on the nutritious pod (carob). bacteria which fix nitrogen from the atmosphere. This allows • Australian acacias have bacteria in their roots which fix them to thrive in nutrient-poor soils. Many of the seeds nitrogen; African ones provide a shady canopy which have an attachment, known as an elaiosome (below), which attracts mammals which provide nitrogen in the form of is rich in protein and oil. This is attractive to birds which droppings. digest the elaiosome, and pass the seeds. It also appeals to • In Australia, pods and litter around the acacias create ants which ‘plant’ many seeds by carrying them intense fires which can kill the trees but provide good underground into their nests. The hard, water- conditions for seeds to germinate and grow. In Africa, resistant coat of these seeds can only be fractured mammals attracted to the trees remove grass and keep by high temperatures or abrasion which means firesmild.

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3 Tropical woodlands Althoughtropicalwoodlandsaredominatedbyeucalypts,melaleucas and acacias, there are many other significant and conspicuous trees. Palms Coryphapalms(Coryphautan)(left) characteristicmopsofspikyfoliage,oftenfire-blackenedtrunks grow, sometimes in extensive and long flower spikes, they are a common sight in tropical groves, where they are subjected woodlands. Older plants may have branched trunks. Grass to seasonal flooding. Reaching treeshaveareputationforgrowingslowlybutsomespecimens 20-25minheight,thesepalmsmay havebeenknowntoreachheightsofnearly2minjust20years, be 40 or 50 years old before they so the ages of large specimens may sometimes be exaggerated. flower for the first and only time. The roots of young plants can contract, pulling the stem below They then die. The fan-shaped ground level. It may be many years before it fronds begin to fall before this appears above ground to form a trunk. occurs so the multi-branched Grasstreesarewelladaptedtofire.Theleaves, flowerstalks,whichcanbeupto5m whicharerichinresin,arehighlyflammableand in length, appear at the top of a fireseemstostimulateflowering.Alongspike, largely leaf-less trunk. The flowers covered with tiny flowers, grows up from the are tiny but there are millions of crown at a rate of 4-10cm a day, eventually them. Fruits take about 18 months to mature. reachinglengthsofthreeorfourmetres.These There are about 20 species of Livistona palms in Australia. flowersproducelargeamountsofnectar They are about the most drought-resistant of all Australian which attracts birds, insects and small palms and can be found growing, as single specimens or in possums. Resin is produced in the leaf groups,inopenwoodlands,alongsideeucalypts.Someflourish base.Itwasusedtraditionallytoattach in open sunny situations or as part of the understorey in open spear heads to shafts and was an forest where they are subjected to, and survive, frequent fires. importanttradeitem;analysisofresin Others prefer wetter areas. They can even be found right in the on ancient spear heads has been used driest centre of the continent where rocky areas ensure some to work out trade routes. Hundreds of permanent moisture. These are thought to be relicts, dating tonnes of the resin were exported to back to times when the climate throughout the continent was Germany and the USA in the nineteenth much wetter and palms would have been much more common century. It was used in varnishes, metal lacquers,woodstainsandexplosives.The Grass trees flowerspikesmakegoodlightweightspears and fire sticks. Grasstrees(Xanthorrhoeasp)flourishindryplaces.Withtheir

Softwoods Manywoodlandtrees,suchaseucalypts,arehardwoods,buttherearesoftwoodsamongthem,notablythekurrajongs. Bottle tree Theyareoftenfoundonrockyoutcrops.TheyhavelinkstorainforesttreesandmosthaveancientGondwananorigins. (B. rupestre) Boab trees (Adansonia gregorii) are distinctive features of to have evolved to cope with drought theKimberleyregionofWesternAustralia.Theyarealsofound conditions. They tend to drop their leaves innorth-westNorthernTerritory.Theimmense,swollentrunks in the dry season and several species have on older trees can measure over 15m around. Radio-carbon swollenstemsforwaterstorage.Manyof dating of a related species in Africa indicated an age of 1000 the species which grow in tropical years. Given their slow growth rate and the immense size of woodlands are commonly known as some trunks, large Australian boabs are also likely to be very kurrajongs. old.Thelargewhiteflowers,whicharepollinatedbyhawkmoths, appear on the spreading branches of the tree when it has Thenorthernkurrajong(B.diversifolius) dropped its leaves. The name boab is a shortened version of the is found across the north. Its leaves vary African ‘baobab’. enormously as it grows. Simple leaves on young seedlings go through about six distinct changes, Boabs are a puzzle. In spite of their trunk shapes, they are not becoming more lobed as the tree grows. This tree spends much related to Australian ‘bottle trees’ (Brachychiton sp.). Their of its early life developing a huge, deep tap root. closest rellies are six species in Madagascar and one on the African mainland. It has been suggested that seeds, or even The red-flowered kurrajong (B. paradoxus) entire trees, arrived in Australian after floating across the (left) has, as the name suggests, beautiful red Indian Ocean – but this theory runs into trouble because there flowers which form clusters along the are no closely related species in Madagascar, unless they have branches when the tree is leafless. Some of sincebecomeextinct.Alternatively,thesetreesmayhavebeen the flowers are male and some are female. in Australia since before the break-up of Gondwana. If that is This tree occurs in northern Northern thecase,however,whyhavetheynotspreadfurther,sincethey Territory and Queensland. are well adapted to drought conditions? Possibly the superior Three species of kapok trees and bushes root systems of eucalypts have given them a competitive edge. (Cochlospermum spp) are found across the north, in open Fire, however, may play a part. Studies have shown that woodland.Theygrowparticularlywellonrockyhillslopesand although young boabs can resprout successfully from the ridges. These trees drop all their leaves during the dry season roots after a fire, they bear very few fruits. On the other hand, but become covered at this time with bright yellow flowers. inareaswhereovergrazinghasledtoareductionoffires,boabs These result in large, green, barrel-shaped fruits up are spreading rapidly. to 8cm long which, as they mature, become brown Kurrajongs andsplittoreleasemassesofsilkyhairs,embedded withseeds (right).Eachseedhasalittleparachute Most (29 of 31)) of the trees belonging to the Brachychiton and can be dispersed by the wind. The kapok has family are endemic to Australia. They are found growing in a been used as cottonwool—for stuffing variety of situations from rainforest to woodlands but all seem cushions—and in Aboriginal body decoration.

4 Cycads Grevilleas Cycadsofvariousspeciesare Although there are more than 200 to be found in the species of grevilleas in Australia, Dryander’s understoreyoftropical they are poorly represented in the grevillea woodlands. These are tropics when compared with the ancient ‘dinosaur’ southern part of the continent. plants which date back However, they can form stands 230 million years, long before where conditions are suitable. flowering plants evolved. Separate maleandfemaleplantsproducecones, Grevillea flowers are rich in not flowers. These plants are able to nectarandattractalargenumber increase the temperatures of their ofbirdsandinsects.Mostflowers mature cones up to 17deg. above the have a series of long, protruding localairtemperature.Thisusuallyhappensintheafternoonand stalk-like ‘styles’. Before the bud may serve to attract pollinating insects (usually weevils) by opens, the sticky end of this style enhancing the odours of the plant. It may also help the male collects pollen from the surrounding cones to shed pollen. stamens. When the bud opens it is ready, in a prominent position, to deposit the pollen on Cycads have unique root structures, which look like corals. visitinghoneyeaters,whichthencarryittoanother These contain symbiotic blue-green algae/bacteria which are plant. able to fix nitrogen from the air, thus allowing these plants to thrive in poor soils. Studies in have shown Dryander’s grevillea (G. dryandri) is a low shrub that cycads there can fix up to 35kg of nitrogen per hectare per which is widespread across northern year.Cycadsintropicalwoodlandsareoftenburntbutrespond Australia. Its flowers vary in colour from cream to with a crown of fresh leaves. Fire also seems to stimulate pink and red. production of seeds: a comparison of burnt and unburnt The bushman’s clothes peg,(G. glauca)isa areas showed that cycads in the former produced over seven species found in Queensland. Its common times more seeds. All parts of the cycad are poisonous, the namecomesfromtheveryhard,woodyfruits toxins including mercury which is obtained from small whichsplitpartiallytocreateidealemergency quantities in the soil. (For more on cycads, see Tropical clothespegs,orpaperclips.Theyareroughly Topics59.) circular with a diameter up to 4cm.

Serious chemicals Withtheirspreadingcrowns Heart-leaf poison bush is a straggly, multi-stemmed bush of bright green leaves, which grows to about 2m. Leaves are grey-green, often with a groups of Cooktown notch at the tip. The large flowers are red and ‘pea-shaped’; a ironwood(Erythrophleum shrub in full flower makes a spectacular display. chlorostachys) (right) stand out from the crowd. Matchwood,orturpentine(Erythroxylumellipticum)isafairly In spite of its name, this unremarkable small tree found across the north but it has some tree is common throughout notorious cousins – related species in South America are the northern Australia, not just sourceofcocaine.NoneoftheAustralianspeciesproducethis, aroundCooktown,growingonwell-drained butdocontainsomeinterestingcompounds.Thetimberisvery soilsinassociationwithbloodwoods,stringybarks durable, burns when wet and yields a beautiful red heartwood which is popular with wood turners. and other eucalypts. It is a highly poisonous tree, Seed pods known in parts of Western Australia as ‘camel poison’. Allpartsofthetreearetoxic,evendryleaves,althoughitseems Fire! that little corellas can eat the seeds. Suckering shoots are Along with drought, fire is one of the greatest trials facing particularly dangerous. Domestic animals have been poisoned vegetation in tropical woodlands, and trees living in savanna by leaves accidentally trapped in the side of trucks which were transporting them; 50g of leaves is enough to kill. Do not tie landshadtoevolvestrategiesforsurvivingitlongbeforehumans your horse to this tree! enteredtheequationwithfiresticksandmatches.Thethickbarks ofmanytreesareagooddefence,whilesmoothonesgivelittle On the plus side, the hard timber, which is one of the densest of any Australian tree, is resistant to termites. It was widely used for the fire to catch on to. Most sclerophyll trees have special by early settlers for railway sleepers and fence posts. epicormicbudsprotecteddeepbelowthebarkwhichwillsprout Traditionally,Aboriginalpeoplehavemadegooduseofthehard if the main foliage is badly damaged (right). Woody swellings timber. Infusions of the leaves have been used to cure scabies aroundtheroots–lignotubers–canalsoshootifnecessaryand whileburninggreenleavesrepelmosquitoesandsandflies.The somespecies(suchasDarwinstringybark)produceextensive tree produces creamy green flowers in spikes which eventually turn into flat, brown, woody, seed pods up to 14cm long. root suckers. Fire-sensitive trees may avoid the problem by creating dense stands and dropping abundant leaves to sup- Heart-leafpoisonbush(Gastrolobiumgrandiflorum)whichis press the growth of fuel (grass). found across northern Australia, contains the poison 1080 (monofluoroaceticacid),whichisextremelypoisonoustomany Many woodland species have woody pods which protect the introduced animals. There are 27 species of Gastrolobium sp seedsfromfire,althoughtheheatoftenstimulatesthemtoopen in Australia. All are thought to be poisonous and 18 are known and release their seeds, at the appropriate moment, into a to contain toxic amounts of 1080. All except heart-leaf poison nutritiousashbed.Somehardseeds,suchasacacias,needheat bush are found in south-western WA (where the seven species of Oxylobium plants containing 1080 also occur). It seems to stimulate germination. However, recent experiments have native mammals and birds in this region are not killed by the shownthatitmaybethesmoke—possiblyammoniawithinit— toxin, having evolved alongside these plants. So 1080 is often ratherthantheheatwhichtriggersgerminationinsomespecies. usedforfox-baitsinWAbecauseitisconsideredsafefornative animals.

5 Questions & Answers Facts and stats Over 900 species of acacias have been Q Couldmorespecificinformation plants to evolve. New environments recognised,butnotallhavebeennamed. begivenonhowweknowthat created, and the microclimates About 275 species occur in northern floweringplantsfirstevolvedin present in these valleys, would have Australia. westernAfrica? given the plants opportunities to become established while the variety Smooth-barked eucalypts earned the A The oldest fossilised pollen, of habitats would have encouraged name ‘gum trees’ because they were the about 124 million years old, has been diversity. Compared with the non- first recognised, by European botanists, found in what is now western Africa. flowering plants, the new models had to produce a lot of gum-like sap (kino). At that time the world’s land many advantages. They had the masses, previously contained in the required genetic potential to adapt to Seeds of most acacia species remain supercontinent, Pangaea, had split new conditions. They also had better viableforupto20years.Manyrequire in two with Laurasia in the north and seeds and better distribution heattogerminate–incultivation,seeds Gondwana in the south. Gondwana mechanisms. Rapidly evolving are sometimes dropped into recently was composed of South America, relationships with insects, mammals boiledwatertobringthemtolife. Africa, India, Antarctica and and birds, and the use of Australia. A concentration of early sophisticated pollination Notable among deciduous eucalypts is pollen types in rocks about 120 mechanisms, led to the speedy the broad-leaved carbeen (E. million years old in western development of varieties available to confertiflora) which is widespread in Gondwana suggests that this region take advantage of changing tropical woodlands across northern was a major centre for the evolution conditions. Australia. New leaves sprout initially of flowering plants. This centre was with an attractive purple colour. The situated in an area where a vast rift Acknowledgements to The Nature of large-leaved cabbage gum (E. valley was developing between Hidden Worlds by Mary E. White. grandiflora), found across the north, northern South America and North withitsmaindistributionintheNorthern Africa (see map). From here, Q Ihavebeentoldthatpythonsin Territory,andapplegum(E.polysciada), flowering plants were able to spread theForsythareabreedwithking from the Top End, also drop their leaves. across Gondwana. The oldest pollen brownstoproduceaparticularly found in Australia is about 110 aggressiveandvenomoussnake. Livistonapalmsbelongtoanancientand million years old and comes from the primitive group. Fossils date back 65 Great Artesian Basin. It does not A This is absolutely impossible. and even 69 millions years. belong to any existing plant family. They are completely different species of snakes. In fact, they belong to Eucalypts, of about 40 species, cover 64 Flowering plants seem to have different families. If pythons and king percent of the total area of Cape York diversified to produce many families browns could breed together, then so Peninsula.Eighteenspeciesofmelaleucas relatively quickly. It is thought that could dolphins and rats. Colour and cover about 14 percent of the area. Two the rift valleys, produced as patterns of snakes can vary greatly species, Eucalyptus tetrodonta and continents pulled apart, would have within the same species from one Melaleuca viridiflora, dominate. provided good conditions for these area to another, leading to confusion over identity. This may be source of Sclerophyll plants include eucalypts, some of these commonly believed melaleucas, acacias, grevilleas and myths. It is also rumoured that banksias.Thewordsclerophyllcomes taipans can breed with pythons – an fromtwoGreekwords,sklerosmeaning equally impossible idea. ‘hard’andphullon,meaning‘leaf’.

Although they are not venomous, Researchers subjected the seeds of 94 pythons will bite if provoked. WesternAustralianplantstocoldsmoke Bacteria in their mouths could cause and to water through which smoke had the bite to become infected, so it is a beenpassed.Germinationratesincreased good idea to be cautious with all significantly after this treatment. snakes, whether venomous or not. SclerophylltreesinsouthernAustralia seem to have a particularly strong relationshipwithfire–eucalyptsthere contain more flammable oils in their Tourist talk leavesthanthosetothenorth. ENGLISH GERMAN JAPANESE Acacias are not the only plants to woodland Waldland shinrinchi dispense with leaves. A number of small shrubs of the Bossiaea genus (there are drought Dürre kanbatsu 50 species altogether) are common in leaves Blätter ha tropical woodlands. Their ‘green bits’ juhi are flattened stems, known as cladodes. bark Borke These are not phyllodes, which are trunk Baumstamm miki flattenedleaf-stalks.Theyaregrey-green stem Ast kuki and have prominent notches where the remainsoftheleavesmaybeseen.These bud Knospe tsubomi plantsareknownlocallyinsomepartsas thick dick atsui ‘ferns’, but the pea-shaped flowers, transpiration Verdunstung hassan which spring from the notches, show deciduous jährlicherLaubfall rakuyoseino that they are flowering plants.

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6 Out and about A page of seasonal happenings and events, natural andotherwise, not necessarily related to the general theme of the newsletter. Cicada birds tend to keep out The wet season sees the return of Avegetationmapofnorthern of sight, foraging in the upper leaves to the branches of Australia was produced recently. foliage for insects, a habit those deciduous trees which A Tropical CRC which makes them seem rarer dropped them as a water- project, this map was created by than they actually are. At saving strategy during the Dry botanists from Queensland, the nesting time, however, (see page 1). Those on the batswing and Western the male suddenly finds coral tree ( vespertilio) have Australia. his voice – a loud, high- a distinctive shape which have earned pitched buzzing, reminiscent of the tree both its common and its cicadas – which gives away his specific name – vespertilio is Latin for presence. The dark plumage of the ‘bat’. The precise shape of the leaves male and the brown feathers of the varies, depending on locality, and this female, however, still make these shy is a versatile tree, growing across the birds difficult to spot. northern half of the continent from drier rainforest to desert. Nesting can take place between The project involved October and March, but is mainly from integratinginformation November to January. A shallow cup from existing maps of of fine twigs and other vegetation is various scales as well as filling in the woven together with cobwebs and gaps where no maps existed. In digital decorated with lichen and moss. Only (1:1millionscale)andprinted one egg is laid, the female doing all the (1:2million)forms,themapsare incubating. If the nest is disturbed the valuable for students, researchers and birds have been known to dismantle it planners. Printed maps can be and use the materials to build The bare branches of this tree obtained from Kathryn Thorburn, Ph: elsewhere. These birds are found are covered with bright red (08)89466754.Fordigitalcoverage, across most of the north and down the flowers between July and contact John Neldner, Ph: (07) 3896 east coast as far as Melbourne. They November – a characteristic 9322. A technical report, in press, frequent , monsoon noted in the name Erythrina which should be available as a CD-rom early and paperbark swamps, sometimes comes from the Greek word for ‘red’. in 2002; contact the Queensland moving into adjacent sclerophyll Corkwood is another common name Herbariumon(07)38969326. forests. given to this tree; settlers used the soft bark as brake pads in their wagons. Branches often have thick black thorns which become smoother with age. A number of plants (for example Capparis and Carissa spp) Fruit ripens have thorns while young. This is on the cocky thought to deter herbivores and to apple tree (Planchonia careya) during date back to when the now extinct, the wet season. Large and green, these browsing megafauna were a threat. fruits are more pear- than apple- shaped and contain a thick edible As days and nights grow hotter and ThedraftHinchinbrookMarine fibrous pulp. They are sometimes more humid, insects of many types ManagementPlanisnowavailable. called billygoat plums, but this name is emerge in their adult forms. Cicadas This covers the Hinchinbrook also used for several other species. spend their youth underground. After Management Area and the Family hatching from eggs, laid in slits in Islands Management Area. This area This tree flowers between July and branches, the wingless young drop to is renowned for containing some of November. The large white the ground and burrow underneath. the most outstanding and spectacular flowers have long stamens This phase of their life may last as islands, reefs and waters of the Great tinged pink at the base. They long as 17 years as they gradually Barrier Reef World Heritage Area. The are short-lived, usually metamorphose, becoming more adult combination of the Hinchinbrook opening in the evening and at each change. When mature, they Channel, many and varied islands and dropping by the next morning – a climb out of the ground and up vertical reefs, and the adjacent mainland strategy which would indicate supports where their skin splits and produces a unique environment. nocturnal pollinators such as bats or winged adults emerge. Discarded skins Publication of the draft management moths. Cocky apple is widespread in are a common sight. It is the adult male plan is a major opportunity for public tropical woodlands across northern cicadas which make the deafening involvement in helping manage these Australia, growing in a variety of well- noise. An internal areas. Copies are available from EPA/ drained soils, including the fringes of muscle pulls in a QPWSofficesinIngham,Ph:(07)4777 coastal sand-dunes. The bark, leaves plate on the surface 2822,Cairns,Ph:(07)40466600and and branches have been used of a special drum-like Townsville,Ph:(07)47225211aswell traditionally as a fish poison; organ on the side of the as Reef HQ in Townsville, Ph: (07) chemicals released into the water abdomen, causing it to 4721 2399. It is also on the EPA interfere with the fishes’ ability to click. It is rather like a tin website at: www.env.qld.gov.au/ breath and they rise to the surface, lid being forced in, rapidly environment/park/managing/ where they are easily collected. and repeatedly. Comments are due by 1 February 2002.

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7 Bookshelf Forest Trees of Australia NativePlantsofQueensland Vols1-4 Wildlife Australia Magazine Autumn D.J Boland et al. KeithA.W.Williams 2001 CSIROPublications(1992) CopyRightPublishing(1984-1999) AtheoryoutofAfrica:Acaciasontwo continents Adetailedguidetoover200treeswith Trees and Shrubs of north-west AntoniV.Milewski useful introductions to major genera. Queensland Jenny Milson Australian Geographic No 61 Jan- PlantsoftheTropicalWoodland DPIQueensland(2000) March 2001 Mike Clark and Stuart Traynor GreatAustraliansurvivor(wattles) Conservation Commission of the AFieldGuidetoEucalypts Vol3 NorthernTerritory(1987) Ian Brooker and David Kleinig TREE Vol 14 No 1 January 1999 InkataPress(1994) Ecophysiologicaltraitsofdeciduous An introduction to 64 plants, aimed at and evergreen woody species in the the layperson/schools. A guide to 280 species north of 26deg. seasonallydrytropics. latitude. DerekEamus NativeplantsofNorthernAustralia John Brook Eucalyptus, an illustrated guide to Australian Journal of 1997, ReedBook(1993) identification 45, pp893-904 Ian Brooker and David Kleinig Observations on the demography of 450 species described in detail. ReedNewHolland(1999) the Australian boab (Adansonia gibbosa) in the North-West of the CommonPlantsoftheKimberley A guide to 200 of the most common NorthernTerritory,Australia. Kevin Kenneally et al. Australian species. D.M.J.S. Bush Books: CALM Bowman CapeYorkPeninsula–anaturalhistory A pocket-sized booklet: illustrated Dawn W. Frith and Clifford B. Frith guide to 32 species. ReedBooks(1995)

This newsletter is produced by the Environmental Protection Agency with funding from the Cooperative Research Centre for the Sustainable Development of Tropical Savannas, the Cooperative Research Centre for the Great Barrier Reef World Heritage Area, the Wet Tropics Management Authority and the Great Barrier Reef Marine Park Authority. Forfurtherinformationcontact... Opinions expressed in Tropical Tropical Savannas CRC StellaMartin Northern Territory University Topics are not necessarily those of The Editor DARWIN NT 0909 the Environmental Protection Agency Tropical Topics Ph: (08) 8946 6834 . Environmental Protection Agency CRC Reef Research Centre PO Box 772, While all efforts have been made to POBox2066 TOWNSVILLE QLD 4810 verify facts, the Environmental (10 - 12 McLeod St) Ph: (07) 4729 8400 Protection Agency takes no CAIRNS QLD 4870 Great Barrier Reef Marine Park Authority responsibility for the accuracy of PO Box 1379 information supplied in Tropical Ph:(07)40466674 TOWNSVILLE QLD 4810 Topics. Ph: (07) 4750 0700 Fax:(07)40466604 © The State of Queensland. e-mail:[email protected] Wet Tropics Management Authority Environmental Protection Agency PO Box 2050 2001 CAIRNS QLD 4870 Ph: (07) 4052 0555

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