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Tropical Topics An interpretive newsletter for the tourism industry

Plants without , mosses, and No. 61 April/May 2000 Mini-ecosystem on a Notes from the In the we tend to concentrate on the big picture — the whole forest, the magnificent and any we can spot in and around them. We focus on Editor the fresh green (or new red) and tend to ignore those which look a bit Following on from the December blotchy, dirty and old. However, a closer look may reveal an entire ecosystem, issue of Tropical Topics (No. 59) with whole communities of tiny and animals flourishing right there on which focussed on , this the surface of the leaf. issue looks at the other main groups of plants which manage The little plants which live on leaves many leaves are shiny and without flowers. They have ancient are called epiphylls. ‘Epi’ means their shape, designed to encourage origins and flourished back in ‘upon’ and ‘phyll’ means ‘leaf’. to run off quickly, is thought to Mesozoic times when dinosaurs (, the more familiar name used reduce the ability of epiphylls to roamed the earth and flowering for a number of ferns, orchids and so colonise them. plants had not yet made an on, means ‘upon-plants’.) Epiphylls appearance. include a variety of non-flowering Nonetheless, epiphylls are an plants including lichens (the main important part of the whole Botanists who study these plants group), mosses, leafy liverworts and rainforest ecosystem. They are can only dream of the time when algae. Twenty , or more, may also a sensitive bunch and can ferns formed and conifers be found on a single leaf. They be disturbed by human proliferated in the southern flourish best where light levels are low, activities. Loss of hemisphere as well as to the north. on leaves in the understorey. Indeed, has left They consider these plants to be almost every understorey leaf them vulnerable now in their ‘sunset years’, in the supports at least a few of these plants and recent process of being superseded by the research dominant angiosperms. and among them an entire Nonetheless, the plants we see microscopic fauna population of mites, suggests that today are the survivors. Some, such worms and insect larvae as well as some may as the ferns, giant clubmosses and a number of fungi function as and giant horsetails became extinct. species. We often talk of good However, despite competition from in in terms of the indicators flowering plants which were able to bewildering number of species but of forest reproduce more efficiently and the variety of microscopic epiphylls stress. adapt to different conditions more and their dependent animals make a quickly, an impressive and very valuable contribution to this. fascinating variety of non-flowering plants have held their ground. Many of the bacteria which live on leaves play an important part in the Tour-op tip rainforest ecosystem by using Take a magnifying glass or hand nitrogen from the atmosphere and lens with you into the rainforest to recycling . However, show visitors the leaf-top epiphylls can be quite a burden for a ecosystems. However, please bear . A heavy population of them on in mind that epiphylls are sensitive. a leaf significantly reduces its ability Handle the leaf with care (do not to photosynthesise (produce food break, tear, squash or remove it) from ). To discourage this and avoid touching the epiphylls. I would like to thank Gary Wilson of the Queensland for An excellent small brochure with coloured, magnified photos, has been his very valuable assistance with produced by the Rainforest CRC. Miniature Gardens on Rainforest Leaves: A this issue. guide to common epiphylls in the Wet Tropics can be obtained by contacting them on Ph: 4042 1246 or via PO Box 6811, Cairns, QLD 4870. Small and flowerless Algae Lichens could perhaps be regarded as terrestrial algae. were the They are remarkable organisms. Each is a combination of an first alga (blue-green or green) and a , functioning proper together in a symbiotic partnership. The fungus provides the plants to ‘ system’ (hyphae), drawing up water and minerals for the evolve and pair. The rootless alga has the chlorophyll, the green stuff in Foliose most plants which enables them to photosynthesise — to create food from are the ancestors of all of today’s land sunlight. To do so the alga needs the water provided by the fungus, while the plants. They are very simple cellular fungus needs the food manufactured by the alga. Together they are a lichen. plants, with no , stems or flowers. Generally the fungal threads create the body of the lichen with the algal cells While most are found in water bodies, living within them. This gives the lichen strength and prevents the alga from salt and fresh, the notorious blue- drying out. The fungi also manufacture a type of acid which serves to eat away at green algae forming blooms where underlying rock and provide the lichen with a foothold. Lichens therefore erode loads are high, others are rock, very slowly. It has been estimated that they produce a centimetre of topsoil found on land where conditions are in two thousand years. moist. Small forms grow as parasites below the ‘skin’ (the cuticle) of Many lichens produce small powdery granules called soredia on their surface. rainforest leaves. These contain both algal cells and fungal threads. When washed or blown away, or carried by insects, they grow into new lichens. Larger upright packets (isidia) Mosses represent an evolutionary work in a similar way. However, sometimes the fungal partners make their own step up from algae. They have no fruiting bodies. These vary in appearance, resembling small volcanoes, cups or roots and no system of woody vessels jam tarts. When these burst, the fungal are dispersed but if they do not which allow more advanced plants to pair up with the correct algal cells they cannot develop. (The algal cells, on the grow tall. As the first land plants other hand, are able to live independently.) mosses probably created the first forests, mini-ecosystems just 5cm or Lichens grow on rocks, walls, trees, fences, roofs and on the ground, as well as so high, achieving this impressive on leaves. They are limited by light, needed by the algae for , and height simply by packing themselves also need clean air. The presence of sulphur dioxide, produced when fuels such tightly together. as coal and oil are burned, and which is responsible for acid rain damage, kills capsules lichens. These plants are therefore good indicators of a clean There are three main types environment. Since some are more . tolerant of pollution than others, the of lichens type of lichen growing can tell us how Crustose bad the pollution is. However, lichens lichens form are very hardy in natural conditions, flat crusty living in the tropics, on mountain tops, plates. They in salty seashore splash zones and grow very The sex even polar regions, where they survive slowly outwards of temperatures well below freezing. They around the margin, mosses can stop growing if conditions are dry, increasing their radius by resembles the resuming when moisture returns and as little as 0.5mm a year. complicated system of are usually the first organisms to alternate generations found in algae. invade barren ground, such as new However, mosses keep the next lava flows. Here they provide a generation at home! Whereas algal foothold for other plants to move in. male and female cells meet by swimming freely through the water, female moss cells are attached firmly to The human element the parent plant. When they have Lichens were used traditionally in been fertilised by free-swimming male many countries to make dyes for cloth, Foliose cells they grow into spore-filled notably Harris tweed, in Scotland. The lichens capsules on the end of long stalks. dye litmus is also derived from lichens. are leafy in appearance, although These capsules eventually open to It changes to red when exposed to an the lobed or branched structures are release the spores which are blown acid and blue when exposed to an not true leaves. They often grow away to grow into new moss plants. In alkali. An infusion of the lichen near mosses. some respects, this tendency to retain lungwort was used for treating coughs the female egg on the parent plant and asthma. resembles the habit of later plants, such as cycads, conifers and flowering Reindeer ‘moss’, the staple diet of plants, to do the same. Perhaps it reindeer and caribou in winter, when represents a step along the nothing else grows, is actually a Fruticose evolutionary way. lichen. Unfortunately, because lichens lichens tend to accumulate certain are even Liverworts are very similar to environmental contaminants, after the more finely branched and may hang mosses. However, where the pointed Chernobyl nuclear power plant down like beards from branches or ‘leaves’ of mosses are arranged in accident in 1986 reindeer ‘moss’ grow up from the ground like tiny spirals on the stems, liverworts have accumulated so much radioactivity shrubs. These last two are rounded (liver-shaped) ‘leaves’ which that the Saami people who live in the particularly fussy about clean air grow flat in double rows. were unable to eat their but grow faster than the crustose reindeer. lichens.

2 Out and about At this time of year the weather About a year ago, in Out and About patterns are changing, our rain coming (Tropical Topics No. 54), you may not from the monsoon trough which remember a mention of an apparent has retreated back towards the equator coincidence between cyclones and but from the south-east trade winds. flowering golden pendas Instead of thunderstorms and dramatic (Xanthostemon chrysanthus). In 1997, torrential downpours we will approximately five weeks after Cyclone experience a more steady type of rain. Justin, the golden pendas were With the return of the south-easterlies, blooming magnificently in Cairns. In conditions on the Reef will become 1999 they performed the same feat five choppier. weeks after Cyclone Rona. Botanists thought it may be a coincidence — but Life in the estuaries changes as the this year, exactly five weeks after Wet declines with many fish choosing Cyclone Steve, residents in Cairns will this time to spawn. Without the recall that our streets and parks were flooding rains flushing out the rivers, golden once again. the water becomes cleaner and, as the saline influence moves further inland, Botanists in Townsville are now some fish retreat upstream. keeping a sharp eye on the trees there. If there is a connection, they can As we look forward to the dry season expect a golden treat around May 7, ahead, the change marks five weeks after the visit of the end of a time of plenty Cyclone Tessi. If for many other animals. you live in Insect numbers decline as Townsville, keep an the weather becomes eye out for this. drier and cooler so frogs, birds, reptiles Some items, past their 'use-by and other animals which eat them are date', have been removed from making the best of them the web version of the newsletter. while they last. Along the beaches, fruit has been dropping from Alexandrian laurels Frogs can still be heard calling but this (Callophyllum inophyllum). The name doesn’t mean that they are breeding. ‘Callophyllum’ means ‘beauty leaf’, Male frogs are compelled by instinct chosen for the large glossy dark green to call as a reflex to rain — but do not and densely veined leaves. The round take if further than that. Times ahead fruits are often dispersed by sea water will be particularly challenging for the where they can float for four months young frogs which have to compete due to the oily seed and the air in the with each other as well as with the tissue between the seed and its shell. adults for diminishing food supplies. The oil, which is poisonous, has been used for lighting and to make a bright yellow soap. The outer grey-green Not many rainforest trees are fruiting flesh is eventually lost, leaving the at this time of year which makes life fruit covered with fibrous brown difficult for young cassowaries which strands. are being evicted from their father’s range as he turns his attention to Resilient to cyclones and tolerant of producing the next generation. One salt, this tree grows exception is the black bean tree right on the shoreline (Castanospermum australe) which has and is one of the been dropping its large leathery pods best species for full of chestnut-like . These coastal protection seeds contain the toxin saponin but and . have traditionally been a staple food for Aboriginal people who remove the toxin through a long process of soaking, leaching and roasting the beans. The trees are particularly Please note common alongside rivers where their that you are welcome to photocopy red flowers sprinkle the ground in Tropical Topics newsletter. spring. The bark of the trunk, when However, if the text is reproduced scratched, smells remarkably like separately it must not be altered cucumber. and must acknowledge the Environmental Protection Agency as the source. Illustrations must not be reused separately without permission. Please contact the editor (details on the back page) if in doubt.

3 Ferns Most ferns love the tropics where the warm moist conditions, not unlike those in which they evolved, suit their requirements. As a result the Wet Tropics is home to a wide range of relict ferns — species which have survived from the earliest times. They represent all the major evolutionary groups. Ferns — the advanced model In the evolutionary development of plants, ferns represent a great advance on all previous models. Whereas all the surface cells of an aquatic alga are able to absorb water and nutrients, on land it is necessary to divide up the tasks, a step which makes the plants more adaptable.

• Roots were a revolutionary new feature dedicated to seeking out Sexual links with the past less accessible sources of water, thus allowing plants to move Although ferns are structurally more advanced than mosses, inland. They also served to stabilise the larger models. like the more primitive algae and mosses their sex life involves two generations and a dependence on water. • Water and nutrients, taken up by the roots, had to reach other parts of the plant so a plumbing system — the vascular system — • Spores are produced by the fern plant evolved. Woody vessels () performed this function, moving in spore cases, usually beneath the water and nutrients upwards. These vessels had a duel function, leaf. providing rigidity to the tissues. With these load-bearing structures the plants were able to grow much taller and reach up to • When released, each spore grows into a tiny the light. heart-shaped structure known as the thallus which, in turn, produces male sperm cells at the • Leaves were another fern invention — a system of solar panels pointed end and female cells in the notch. dedicated to capturing the energy of the sun and turning it into thallus food. Exposed to the air, these had to be sealed to prevent the • In the presence of water, the sperm burst free from the thallus water gathered by the roots from leaking away so a waxy skin and, attracted by chemicals, swim to the female cells. (cuticle) was developed. Since the process of photosynthesis requires an intake of from the atmosphere and • Following , an adult plant develops, waste oxygen must be released, special design features in the eventually dwarfing its ‘parent’ thallus. Curiously cuticle — pores — allowed this exchange of gases to continue. this large spore-producing fern plant is the equivalent of just the tiny spore capsule and stalk • Another plumbing system was needed to of the moss plant while the much more obvious move the sugars and other photosynthetic xylem green moss plant is the equivalent of the tiny fern products from the leaves to the rest of the phloem thallus; both produce sex cells. plant. This function was performed by another new system of vessels, the phloem. Many ferns can, of course, increase their numbers asexually by spreading their rhizomes — stems which are either below the Although ferns were among the earliest vascular plants (algae, surface or just above it. Roots grow down from the lichens, mosses and liverworts are all classed as non-vascular rhizomes while fronds sprout from the top. plants) they were not the only ones. The fossil records tell us that at one time the world was dominated by massive clubmosses, giant horsetails and others which created magnificent forests 45m or more in height as they used their newly developed vascular systems to reach higher and higher in competition for sunlight. Many of these plants are now extinct, their relatives hanging on in comparative obscurity.

Forty fern species are Coral ferns endemic to the Wet Tropics. Coral ferns (left & above) are scrambling ferns which form tangled masses. The multi-forked fronds, which form almost geometrical patterns, can grow to 4m on a long, brown, wooly stalk. They are Water ferns found in large colonies in a variety of wet sunny sites. They like Certain ferns live in water. Some have their roots to have their roots in water and their fronds in the sun. in the mud while others are free floating.

Nardoo (Marsilea species, left) is an unusual fern with leaves Filmy ferns which look like four-leaved These are extremely delicate ferns with leaf blades just one cell clovers. It grows in swamps and Gleichenia dicarpa thick. They grow best in humid tropical conditions because the still lakesides with its roots and entire leaf surface is open to the atmosphere and they can dry creeping stems in the mud and its leaflets floating out very easily. on the water surface. (The early explorers, Burke and Wills, died from starvation while feeding on the starchy parts of this fern. It is thought that chemicals Maidenhair ferns in it interfere with our ability to absorb nutrients.) Popular with gardeners and as house plants, maidenhair ferns (left) usually The dreadful exotic from Brazil, have fine black stems and frilly fan- Salvinia molesta, (right) is a free- shaped leaflets. Some species are floating fern. Groups of three leaves very common in the Wet Tropics, grow along a thin stem. Two of the leaves growing in moist open sites along contain large air spaces and act as floats river and track banks. while the third is divided into threadlike hairy lobes which dangle in the water acting as roots to absorb water and nutrients. This fern multiplies vegetatively with great speed, covering water surfaces Adiantum and cutting out light and air to other aquatic hispidulum organisms. 4 Tree ferns There are seven species of tree ferns in the Wet Tropics, three of them endemic. Although all seven are found in the uplands, only two, the scaly, or Cooper’s, tree King fern (Angiopteris fern (Cyathea cooperi) and black evecta) tree fern (Cyathea rebeccae) are Easily mistaken for a trunkless found in the tropical lowlands. The most palm, the king fern produces common and most widespread, the scaly possibly the longest fern tree fern, is also the largest, growing to a fronds in the world, growing up height of 15m with a 30cm thick trunk. The trunk to 7m in length. Fronds usually is patterned with large oval scars left by fallen sprout from near ground level, trunks fronds. It is hardy and often grown in gardens. (butts) developing slowly. King ferns like dimly-lit rainforest stream banks and plenty of water. The related potato fern Unlike conifers and other advanced trees, tree (Marattia oreades) has weeping fronds up to 2m long. ferns are not capable of producing secondary timber. This means that their trunks cannot Like tree ferns both these giant ferns have an ancient history. become thicker, growth occurring only from the top. The trunk is Fossils well over 300 million years old, and very similar to the pithy on the inside but hard on the outside and is often covered modern versions, have been found on most continents. They with a mass of tough aerial roots. If the tree fern is knocked over predate the dinosaurs. these can grow into the ground and develop as normal roots.

Bird’s nest fern The Gondwana connection The name Gondwana, given to the original supercontinent of which was a part, comes from a region of where the fossil seed fern Glossopteris was first described. The widespread geographic distribution of this in ancient times was one of the clues which led to the realisation that the Elkhorn fern continents had once been joined.

Fern allies A 420 million-year-old clubmoss fossil found in Australia is one of the oldest known Basket fern land-plants. Although they once grew as enormous trees, present-day clubmosses are more modest plants, known as fern allies. They are not mosses but the arrangement of Epiphytic ferns their tiny pointed leaves in spirals around the stems is moss-like in appearance. They are Many ferns types grow on other plants, credited with producing the first cones — long before the conifers developed them to using them as perches but not stealing any perfection. These are formed from tightly packed leaf-like structures each of which bears nutrients from them. A number of ferns spores beneath it. specialise in this lifestyle in tropical rainforests because the forest floor is too Fern allies produce two types of spore, small ones which produce gloomy for them to survive and their only male thalli and large ones which produce female thalli. The sperm alternative is to perch on the trunk or must then swim the extra distance to find a female thallus before branches of a tree. They can also survive on fertilisation can take place. rocks and on the ground if there is sufficient light but away from the forest edge it is the species (left) are pretty, multi-branched fern allies spores which land high in a tree which which form low dense carpets in damp shady areas. They too have flourish. an ancient history and once formed forests 40m high. Now they rarely reach more than 10cm in height and scramble along the Brown sterile leaves hold basket, elkhorn ground producing new roots at intervals along the stems. Little and staghorn ferns in place while the green scale-like leaves line the stems. Thin, elongated tips on some leaves photosynthesise and produce branches are the spore-bearing cones made up of modified spores. Trapped dead leaves and other leaves. debris provide nutrients. Tassel ferns This an ancient group of fern allies which has declined Hare’s foot fern dramatically since their peak in the era. The rock This fern (below) is named for the brown tassel fern (Huperzia squarrosa, right) which grows in the Wet Tropics rhizome, or stem, covered with brown today is very similar to 415 million-year-old fossils from Victoria. papery scales which may protrude from the clump, Tassel ferns are , with long dangling stems. Some end in long above the ground, for up to tassel-like ‘clubs’ which are the spore-bearing cones, rather like those on 50cm. It tends to be an Selaginella. However, in H. squarrosa the fertile spore-bearing leaves are epiphyte, growing on the same as the normal leaves, a characteristic considered very primitive rainforest trees, on rocks and indicative of its ancient . or on the ground. Aborigines have Related to the tassel ferns is a vigorous scrambling ground-creeping traditionally boiled the roots version (Lycopodium cernuum) which is common along sunny roadsides. It Davallia and stems to treat looks like a tiny pine tree with little cones on the erect branches. pyxidata haemorrhaging.

5 Questions & Answers Facts and stats Worldwide, there are 26 900 named Q How dangerous are huntsmen under bark and at night hunt over species of algae, 15 000 known species spiders? tree trunks and the ground, possibly of lichens, about 20 000 species of coming inside houses. Badge mosses and liverworts, over 12 000 spiders, however, are more common species of ferns and about 800 species in foliage. of (the conifers, cycads and the ginkgo). Huntsmen spiders do not spin webs but, as their name suggests, hunt In Australia there are 390 native their prey by running it down. The species of ferns, 47 species of fern female (which, unusually in the allies, 38 species of conifers (39 of spider world, does not eat her mate) them endemic) and 69 species of creates a pure white egg sac which cycads — all of them endemic. she guards, or carries with her. The A They are largely harmless. little spiderlings stay with her until The Wet Tropics is home to 65 percent Although sometimes referred to as ready to disperse. of Australia’s fern species, 37 percent tarantulas, they are not. Huntsmen of its species and 21 percent of spiders prefer to avoid people and Although harmless, on the whole, its species. will invariably run away if they come huntsmen spiders may have been into contact with them. They will bite responsible for scaring some people Epiphylls can bio-accumulate metals. if trapped in shoes or clothing but in to death — by appearing in a car and Some in New Caledonia are known to most cases, although the bite might giving the driver such a fright that he accumulate nickel, concentrating it be quite painful, it does not cause or she has crashed the car. from traces in host plants growing in any severe symptoms. (It is always nickel-rich . important to remember that individual Q How can I stop goshawks from sensitivities vary so some people attacking the birds in my aviary? The spore of a clubmoss fern may take may react more severely — but it is as long as seven years to germinate very unusual.) The exception is the A Cover it at the top. This will first of and may not produce sex cells for group of Neosparassus species all prevent your birds from being another 15 years. (previously known as Olios) — the able to see the goshawk, which will shield, or badge, spiders. Their bites prevent them from panicking. Birds Conifers evolved about 280 million can cause illness. of prey such as goshawks, years ago. particularly young inexperienced The bodies of most huntsmen ones, will be attracted to the flapping The twin kauris at Lake Barrine are bull spiders are flattened, their long legs movements which could, in their kauris ( microstachya). A rare stretching out crab-like to the side eyes, indicate an species, the bull kauri is found only at giving some a leg-span of 10cm or injured and 150-1200m within a maximum more. Their shape enables them to fit vulnerable geographic range of less than 100km. into tiny cracks and they often hide bird. A cover This species has a coarse flaky bark. under bark. They move very quickly, also prevents often sideways. Generally flecked the goshawk from Kauri pines get their name from the brown or grey, they are usually well- seeing the birds Maori name of the related New camouflaged. Badge spiders get and taking an Zealand species. their name from the ‘shield’ interest in them. pattern of two or three colours, The Wollemi pine including black, yellow, red, The discovery of the Wollemi pine orange and white, underneath (Wollemia nobilis)has been called the the body. They are yellow- botanical find of the century. This tree, brown above and are not as previously known from fossils, was flat as the other types. By thought to have died out more than 50 day most huntsmen hide Grey goshawk million years ago — until October 1994 when a National Parks and Wildlife Service staff member found a stand of the trees growing in a rugged and inaccessible area of the Wollemi Tourist talk National Park. Although less than 200km from Sydney, in the northern ENGLISH GERMAN JAPANESE sector of the Blue Mountains region, algae Algen sou rui these green dinosaurs were growing fungus Pilz kinrui in a remote gorge almost never visited lichen Flechte chi i by people. Nevertheless, a second stand of the pines was found the moss Moos koke following year. Only 38 adult trees and fern Farn shida about 150 young ones are known to conifer Nadelbaum kyuka shokubutsu exist in the wild. However, this plant spore Spore houshi has now been extensively propagated fossil Fossil kaseki and will soon be available to the public. epiphyte Scheinschmarotzer chakusei shokubutsu The Wollemi pine is thought to belong generations Generationen sedai to a genus previously known only cone (Tannen-) Zapfen kyuka from fossils found in Tasmania and . 6 Conifers The word conifer usually conjures up a vision of cold northern forests of Christmas trees. However, back in Mesozoic Era (250-65 million years ago), when dinosaurs were alive and well, along with cycads they dominated the vegetation of a warm wet world. Although the newcomers, the flowering plants, eventually took over the dominant position, conifers were not overwhelmed. The new dry cool conditions which followed their heyday may not have suited them, but they live on, side by side with their more successful cousins. Indeed, they often tower above them. Pencil Bunya Hoop Kauri Brown The Wet Tropics contains the most The hoop pine (Araucaria pine pine pine pine pine ancient lineages of the conifers. cunninghamii) has gained its name The kauri pines (Agathis species) Thirty-seven percent of Australia’s from the long-lasting bark which rival the hoop pine in height. species are found here and five of the persists in large hoops after the centre Unfortunately many of the most 14 species are Wet Tropics endemics, of a fallen tree has rotted away. magnificent specimens, some of which meaning that they are found nowhere Growing to 50m and even 70m in were over 600 years old, have been cut else. Unfortunately many trees have height, it emerges above other trees — for timber. The twin kauris at Lake been removed by loggers for their although it could have taken 200 years Barrine are 50m in height with valuable timber. to get there. Hoop pines tend to diameters of over 2m. They are reproduce at intervals of up to eight thought to be over 1000 years old. Conifers in the Wet Tropics tend to years at which time one tree is capable grow best in the more inhospitable of producing 500 cones, each Perhaps terrain and are more common in dry containing about 800 seeds. Hoop the most rainforest. However, they are sensitive pine timber is valuable and these trees tropical to fire, so have persisted best in are now grown in plantations in of protected gorges, on steep slopes and southern Queensland. conifers, rocky outcrops or coastal islands, kauri sometimes creating large stands. Fond Bunya pines (Araucaria bidwillii) are pines like a wet Agathis of ridge tops, some indulge in ‘cloud- found in three areas of Queensland — climate and are robusta stripping’ — grabbing moisture from the Bunya Mountains in the south- usually found in areas passing clouds. east and in isolated pockets in the Wet where there is more than 2000mm of Tropics at Mt Lewis and Millaa Millaa. rain a year and no pronounced dry Many of the tropical species defy the Growing to 40m in height, these trees season. Agathis, the scientific name, conventional image of a conifer by have dense rounded crowns with means ‘ball of thread’ in Greek and having relatively broad leaves. In this clusters of leaves on the end of refers to the appearance of the female respect, they closely resemble the numerous horizontal branches. Large cone. Trunks of these trees are ancient leaves which have been found female cones, weighing up to 10kg, are surprisingly cool — try hugging one as fossils; in some cases they are produced at the top of the tree. The on a hot day. almost identical. Broad leaves allow nuts provided abundant food for their owners to make the most of poor traditional gatherings of Aboriginal light when, as young trees, they are people, held every three years when shaded by others in the forest. the crops were heaviest. The Wet Tropics is a centre of diversity for various species of podocarps, often referred to as brown Creating the cones The brush or black pines. They tend to grow on Cycads, conifers and their fellow cypress pine dry ridges or in sandy areas. It is gymnosperms finally eliminated the (Callitris macleayana), difficult to spot these trees as conifers. need for alternate generations — and a the most ‘primitive’of the Not only are their leaves relatively dependence on water — when they pencil pine group, is found in broad, but the male reproductive units evolved seeds which could be rainforest margins, mainly on the Mt resemble tiny fuzzy ‘flowers’ and they fertilised when attached to the parent Windsor and Atherton Tablelands in produce fruits rather than cones. plant. However, one did not develop the Wet Tropics (as well as in south- These fruits have earned the name from the other. They represent east Queensland and NSW). It can ‘plum pine’ for several species. different evolutionary experiments grow to almost 40m in Generally the , enveloped in flesh, Bunya is carried on a very swollen stalk. This with similar results. height with needle- cone like stems and stalk may be brightly coloured, Whereas cycad plants are either male woody cones orange, pink or red, and in most Hoop pine or female, most conifers bear both male which attract cone cases is edible, though not tasty, and female cones which makes wind- sulphur-crested and attracts birds. Seeds of some blown pollination more efficient. When cockatoos to species have traditionally been a pollen grain reaches the female cone gobble the roasted and eaten by Aboriginal it may take as long as a year to grow a seeds. people. tube to the egg. The male sperm is then drawn down the tube (unlike Pencil pine cone Brown pine fruits cycad and ginkgo sperm it cannot swim). The fertilised seed spends up Tour-op tip to a further year in the cone as food Visitors, particularly from the , who have a fixed idea of a supplies and a waterproof coating are conifer with needle-like leaves, are often surprised by our relatively broad- built around it. When it is ready, the leaved conifers. Identify a kauri pine or a podocarp on your route and point it cone dries and opens to release the out. Explain that these conifers are relicts of the earliest ‘dinosaur’ conifers and seeds. Conifer cones are quite that pine trees are a more recent evolutionary development. Casuarinas, on the different to, and more complex than, other hand, have needle-like stems (with tiny scale-like leaves), insignificant cycad ones. male flowers and cone-like fruits — but they are flowering plants, not pines!

Illustrations (except C. macleayana) courtesy Flecker Botanic Gardens, Cairns 7 Bookshelf Australia’s Gondwanan Heritage Tree ferns of the Wet Tropics Reed Books (1993) Interpreting the evolution of Mike Trenerry Australia’s Wet Tropics flora Wet Tropics newspaper Dry season 1998 Both these books focus on the fossil Compiled by Tony Roberts history of Australia, the second with Flecker Botanic Gardens/Cairns City This article provides information on the an emphasis on the ancient plants. Council seven species of tree ferns found in the Wet Tropics. It is always worth looking at children’s This booklet is designed to compliment books in your local library. They are the excellent interpretive walk which is Ferns of Queensland often a useful and colourful source of next to the Flecker Botanic Gardens, on A handbook to the ferns and fern allies information. Two such books are: the corner of Collins Avenue and S.B Andrews MacDonnell St, Edge Hill, Cairns. The Queensland Department of Primary Ferns walk, which starts opposite the side Industries (1990) Theresa Greenaway gate to the Gardens, on MacDonnell St, Green World series is divided into seven zones. Each zone With fine drawings this is a detailed Heinemann (1991) has a sign describing each step in the guide aimed at the botanist. evolution of plants and is surrounded Lichens with examples of the appropriate The Nature of Hidden Worlds Heather Angel species. The booklet reproduces these Mary E. White Junior Nature Series signs along with details of the Reed Books (1993) Angus & Robertson associated plants and gives some (1980) background on Gondwana. It is The Greening of Gondwana available from the office at the Gardens. Mary E. White

This newsletter was produced by the Queensland Department of Environment and Heritage (now The Environmental Protection Agency) with funding from the Wet Tropics Management Authority. Opinions expressed in Tropical Topics are not necessarily those of For further information contact... the Department of Environment and Heritage (EPA). Stella Martin Wet Tropics Management Agency The Editor (For general infomation on the Wet While all efforts have been made Tropical Topics to verify facts, the Department of Tropics World Heritage Area only.) Environment and Heritage (EPA) Environmental Protection Agency PO Box 2050 takes no responsibility for the PO Box 2066 CAIRNS QLD 4870 accuracy of information supplied CAIRNS QLD 4870 Ph: (07) 4052 0555 in Tropical Topics. Fax: (07) 4031 1364 Ph: (07) 4046 6674 Website: www.wettropics.gov.au © The State of Queensland. Fax: (07) 4046 6751 Environmental Protection Agency e-mail: [email protected]