Botanic Gardens Trust, Sydney, Australia


Ask a scientist

Here are some of the questions New South Wales school children - primary and secondary - asked our scientists during our last ‘Ask a Scientist’ program.

Peter Weston

Plants in general

How many kinds of plants are there?
There are more than about 250 000 species of flowering plants, cycads (an ancient group of plants), ferns and conifers.

How many different species of plants are there in Australia?
Approximately 18 500 species of flowering plants, ferns, cycads and conifers. This number includes only higher plants, and doesn’t include lower plants such as mosses, liverworts and algae.

Which plants live the longest?
There is a bristlecone pine tree Pinus aristata in the Sierra Nevada mountain range in western North America which is believed to be 4900 years old.

How long does a Moreton Bay fig live for?
Moreton Bay figs essentially grow in subtropical climates and have a very pithy wood – so they don’t lay down good growth rings like trees in colder climates. They probably do not live much beyond 150-200 years. The oldest known avenue of fig trees in Australia was planted in the Domain in Sydney in 1847.

What is the biggest tree in the world?
The tallest tree in the world is the Redwood tree of California in the USA. The tallest flowering plant (tree) in the world is the Mountain Ash of Victoria, Australia. The largest tree in the world in area is probably the banyan tree (a type of fig tree) in the Calcutta Botanic Gardens, India, which has over a thousand stems. These stems are formed by roots that have grown down from the side branches and thickened into stems, supporting an ever-growing tree. The longest plant in the world is probably kelp, a large brown seaweed.

Are any plants dangerous to humans?
There are no plants that eat people in the way a Venus fly trap catches and eats a fly. Some plants are spiky and thorny and hurt us if we touch them, some are poisonous to eat, and some can cause rashes if brushed against the skin .In Australia there is a tree called a Stinging Tree that has small sharp hairs on the leaves that break off and stay under the skin and itch for a long time.

How can you tell if a plant is poisonous?
The best way to tell if a plant is poisonous is to check in books. Some parts of some plants are poisonous while other parts can be safely eaten. Some plants are poisonous to some animals and not others. Some plants eaten by Indigenous Australians (see Aboriginal bush foods) were poisonous and were only safe to eat after special preparation to remove the poisons. They probably found out by trial and error in the first place. These days a chemist could check the chemicals found in plants to see if they were safe to eat or not, but this would be a time-consuming and expensive process. Never eat any part of any plant unless you know it is not poisonous.

What sort of plants give you rashes?
Plants with irritating hairs or chemicals in their leaves give you rashes. An example of this type of plant is the Rhus or wax tree, which has beautiful orange leaves in autumn. It has been declared a noxious weed and must be removed from gardens because it causes rashes.

Why don’t some trees lose their leaves in winter?
Trees that lose their leaves are called ‘deciduous’. They mostly come from cold climates and lose their leaves in winter when there is not much sunshine and it is very cold. Pine trees are an exception to this general rule. In warmer parts of the world plants often grow all the year round. Leaves grow old, die, and fall from the tree – but the new leaves are replacing them all the time. The Red Cedar (not a pine tree but an Australian rainforest tree) is one of the few Australian rainforest deciduous trees. In the dry areas of Australia some plants lose their leaves when there is a drought, and then grow them back again after it rains.

Are all marine plants highly tolerant of salt?
Yes, marine plants have to cope with all the salts dissolved in sea water or they would die. Water moves into and out of cells by osmosis and all living things have evolved mechanisms to control how much water is taken in or lost.

Why does the sunflower follow the sun?
Plants need sunlight for energy to grow, and they grow towards the light. This is called phototropism. You can test this by growing some seedlings near a window and watch them grow towards the light.

What do plants eat?
Plants use energy from sunlight, and water, air and minerals dissolved in water to make their own food – in the form of sugars and starch. So plants don’t eat as such, but they are eaten by animals for food. An exception to this general rule is the group of plants like the venus fly trap that ‘eat’ insects and other small animals.

Do carnivorous plants digest anything larger than insects?
In the wild, pitcher plants have been found to contain larger insects (e.g. cockroaches, centipedes) but also scorpions, small mammals and reptiles.

What parts of plants produce oxygen?
Oxygen is produced in the leaves of plants, and also in other green areas of plants exposed to sunlight.

What makes a herb a herb?
The ancient Greeks were the first to classify plants into the three categories of trees, shrubs and herbs. In a botanical sense a ‘herb’ is a small non-woody plant that may be herbaceous, biennial or perennial. In the broader sense ‘herbs’ are defined as plants used by people for special foods or food additives, or medicines, or even ritual. In this sense herbs may even be trees. For example bay leaves come from the leaves of a tree.

How long can a plant normally go without water?
Plants are living things and require water to live and will die if they do not have water in their plant cells. Some plants, like cacti and other succulents, have developed special ways to conserve water, and can survive in deserts where sometimes it doesn’t rain for years.

How many kinds of moss are there in the world?
There are approximately 14 500 kinds of mosses in the world.

How do trees grow?
Trees, like other plants, grow from seeds. The seed sends a root into the soil. The root secures the plant firmly to the one spot and collects water and minerals (such as potassium, nitrogen, phosphorus etc.) from the soil. The seed also sends a shoot up into the light and this develops leaves, stems and branches. A tree grows upwards from the very tip of each stem and sideways from the tip of each branch. The main stem becomes the trunk, and all stems and branches become thicker as they grow. Trees obtain carbon dioxide and oxygen from the air and use the energy of the sun to turn carbon dioxide and water and minerals into plant foods (sugars and starches) which help the tree grow. This very important chemical process is called photosynthesis and occurs in all green plants. It is the source of all food for all animals on earth. Photosynthesis also produces more oxygen than it uses, and helps keep the same balance of oxygen in the air for animals to breathe.

How do trees rot?
Trees are living things and when they die they become the food of fungi that consume them for their energy to live, producing gases and minerals in the process. The minerals return to the soil and the gases return to the air - providing the raw materials from which more trees can grow.

Why do insects like plants?
Some insects like plants because they eat plants for their food or lay their eggs on or in plants so that their offspring (e.g. caterpillars) can eat the plants. Some plants have developed chemicals that make them unpleasant or poisonous to insects.

Succulent Garden

Pests & diseases

Is there much research going into the pathology of plants and the diseases that plants contract?
Yes - at universities, in government departments such as the Department of Primary Industry in Queensland, CSIRO, at botanic gardens such as ours in Sydney, and in private industry. There is of course much more research into cultivated plants (grain crops such as wheat, vegetable and fruit crops, garden plants, forests) than into the diseases of native plants growing in the wild, because of the economic importance of the cultivated species. One major initiative is in the south-west of Western Australia, where a lot of researchers are studying the problem of the fungus Phytophthora cinnamomi and the root rot disease that it causes in both native and cultivated forests, affecting both trees and understorey plants in the forests and spreading out to the extensive heathlands of the region.

What’s the best spray to use to get bugs off staghorns?
We do not recommend that you use sprays in your garden. Staghorn ferns are attacked by small round blue-black beetles with four orange-red spots on their backs. You search for the adult beetles and remove them by hand.

What pesticides should we use to control insect pests?
The easiest way to control pests and diseases is to maintain healthy plants. This means that the plant will less likely be attacked. If the plants are attacked we should consider alternative methods before we look at applying pesticides: pick off larger pests by hand, e.g. snails; remove some pests by spraying with the hose, e.g. aphids; spray with soapy (non-poisonous) water; use mixed companion plantings, e.g. garlic - see books for the method; remove and destroy weeds which may harbour pests and diseases; or if none of these methods work try garlic sprays, eucalyptus spray, white oil or pyrethrum.

Click here to find out more about plant pests & diseases.



How often should you water plants?
Applying the right amount of water to a plant is an art. The water needs to penetrate the soil, and not just moisten the top. The ideal soil is never too dry and never too wet. The best way to test is to push your finger into the soil and feel how wet it is. The amount of watering depends on the type of plant and the type of soil. It is better that plants in pots have well-drained soil so that their roots do not rot. It is interesting to note that more plants are killed in the garden from over-watering than by under-watering. Consider these few points. Native plants are more tolerant of dry conditions if water supply is a concern. More moisture is retained in garden beds when mulch has been used. Water by hand and adjust the pressure so as not to waste water. Always water in the cool of the day.

What is the trick to growing a good vegetable garden?
You need to find a good, sunny, well-drained location then build up and prepare the soil prior to planting. Plant the seeds correctly - e.g. plant beans and carrots in rows, plant cucumbers and pumpkins in raised mounds - and at the right time of the year. Choose plants that suit your climate.  You then have to space and week the developing seedlings and water the right amount at the right time. Try to control pests by clean garden practices and by using mixed plants. Then it’s quite easy!

Are there any plants that can be planted with seeds?
Yes, there are all the more primitive plants that have spores rather than seeds. These include ferns, mosses and algae. There are also some seed-bearing plants that naturally produce offspring by asexual means - by producing whole new little plantlets on the edges of their leaves or in their flower-heads. Other species of plants may spread vegetatively by sending out runners above or below ground - think of how Kikuyu grass spreads rapidly into garden beds by sending out runners from the lawns where people plant it. Human ingenuity has also made it possible to ‘plant plants’ without seeds through special techniques such as tissue culture and by taking cuttings from existing plants.

Is it possible to get hold of endangered plants and try to grow them?
Botanic gardens exchange seeds with other botanic gardens around the world to try and grow endangered species. We do not have the resources to exchange seeds outside this network. However our Friends of The Gardens offer seeds from time to time. You can also join a local branch of the Australian Plants Society NSW (formerly Society for Growing Australian Plants NSW) - they have a network across the whole of Australia and their special interest is in growing Australian plants, including rare and endangered species.

How is tissue culture performed in the propagation of plants?
Tissue culture is a general term used for the maintenance or growth of tissues in vitro  (meaning in glass), and can refer to either animal or plant tissues). In vitro propagation, or micropropagation, refers to the propagation of plants in a controlled artificial environment, using plastic or glass culture vessels such as petri dishes or bottles, aseptic (sterile) techniques, and a defined growing medium. First a growing medium is made - it contains all the nutrients a plant requires for growth: salts, minerals, vitamins (growth factors), hormones (growth regulators), sucrose (sugar as a carbohydrate source), water and agar, a solidifying agent. A small volume of the medium is put in a glass jar and, with the lid screwed on, it is steam sterilised under pressure to sterilise it. Second, the plant is prepared for introduction to tissue culture - called induction or initiation. A piece of the plant, usually a shoot tip or piece of stem, 3-5 cm long, is cut off the plant you wish to propagate. It is cleaned by scrubbing with detergent, rinsing in tap water, then sterilising in a weak solution of household bleach (to kill all bacteria and fungal spores), and rinsed in sterile water. The now sterile piece of plant is trimmed and placed into the growth medium in a sterile jar and sealed. It is grown for 6-8 weeks under artificial lights in a room kept at a constant temperature (usually 22-25 degrees C). During this time new shoots grow, which in turn can be cut into pieces and grown. Hence it is theoretically possible to produce thousands of plants from the original source. The plants ultimately produced are genetically identical to the original, so they are all one ‘clone’.

Would it be economically possible for school students to propagate plants by tissue culture?
Tissue culture can be done relatively cheaply using inexpensive equipment. You could use take-away containers containing coconut milk or bananas for your nutrient base. You can keep your plants sterile by cutting them up in a cleaned fish tank, side on. Media can be sterilised using a pressure cooker (with adult supervision!). However, the easiest method is to grow sterilised seeds, and many schools in NSW are doing this.

What are the possible effects of reducing the genetic variability of certain species of commercially-grown fruit and vegetables by means of tissue culture in the event of some disease or catastrophe?
Tissue culture by itself does not reduce genetic variability. This is something that we do by selecting only a small number or even one individual with what we regard as having all or most of the characteristics that we define as being desirable. Some things have been done in the past to try and minimise the undesirable effects of such highly selective procedures - such as seed banks and living collections. In a world dominated by short-term and short-sighted economic policies that require a positive return from cost/benefit analyses within a short time, maintaining genetic diversity has so far ranked very low. The warnings are there - a few years ago the corn crop in the USA was heavily hit by disease. This crop is grown from so-called hybrid seed, produced at great profit from a narrow genetic base. In this case the problem could be overcome because they found sufficient ancestors to the modern crop still growing in Mexico and not previously known outside the small area in which they grew.

Are there any real advantages in growing vegetables and fruits organically?
Technically all plants are grown ‘organically’. However the term has become associated with procedures to produce plant or animal products with no or little use of externally applied pesticides, fertilisers or medicine for stock, on or from land where little or no residues remain from activities that used such options in the past. Such processes should allow for marketed goods that have lower levels of extraneous chemicals in them. If the ideal is realised then most people would agree that there are benefits. Because of the constraints on production, such organically-produced goods will cost more for the forseeable future.

How do grafts grow?
The secret with grafting is to use plants of related groups when they are dormant. This usually applies to deciduous trees in the winter when they have lost their leaves. What usually happens is that two twigs of the same diameter are cut diagonally with a vertical slit in the middle of each diagonal cut, then they are squeezed together and bound with plastic tape and sealed with some material that prevents them drying out. If the growing parts of both twigs - the cambium layer - are matched, the graft will usually take. Another method is called ‘budding’. Here a bud is cut away from the stem to expose the cambium. A T-shaped cut is then made into the bark of the host plant. The bark is then carefully peeled back and the bud placed against the cambium of the host. The bark is then allowed to fold back over the bud. The graft is bound and sealed in the usual manner.

What kind of soil do you plant gum trees in and when do you plant them?
Gum trees grow all over Australia in many different types of soil. Best results can be obtained with deep, well-drained soil. Generally it is best to plant trees in late winter. Seedling gum trees can be planted at virtually any time. It is best to plant them when they are small so that their roots can spread out and help support the growing tree. Don’t plant them too close to buildings or parking lots.

What special care do coastal plants need?
Coastal plants are usually very hardy because they often grow in windy places and in sandy soil. Your plants will grow better if you can give them plenty of water and protect them from the wind.

How many coastal plants are good for shade?
The best shade plants for coastal regions are the plants that once grew in littoral (coastal) rainforests. They include figs and lilli pillies.

Click here to find out more about gardening information and horticultural research.

Spring Walk


What plants are weeds?
A weed is by human definition a plant that is growing in the wrong place (i.e. as far as people are concerned). Weeds are usually plants that come from somewhere else to a place where they previously did not exist. Without their natural enemies to keep them in check (balance) these plants usually thrive and become a nuisance. Some examples of weeds are Bitou Bush, Bindii, Prickly Pear, Asthma Weed, and Water Hyacinth. Weeds can be controlled by direct weeding, or the use of alternative ground covers or mulch, through the controlled use of herbicides, or through biological agents such as insect pests.

Why is morning glory classified as a weed in Australia?
A weed is just a plant that is growing outside of its natural area. This morning glory probably came from South America.

What can you do to get rid of weeds?
The best way to get rid of weeds is to plan a garden with paved areas and ground cover (use low, flat-growing or spreading plants) or by mulching - use woodchips, grass or garden cuttings, or stones.

What can we do to control the week bitou bush?
Because of the shallow root system small plants can be pulled out by hand or larger plants grubbed with a tractor (if appropriate). Plants should be heaped and burnt to destroy developing seed. Do not slash as regrowth occurs from cut stumps. Fire may also be used to help control bitou bush. Spraying should only be used as a last resort.

Are there any environmentally friendly sprays to kill bindiis?
No. If you have a small lawn you can dig them out by hand. Alternatively use other groundcovers, or turn your lawn into a garden. Generally spraying is not recommended.

Click here to find out more about weeds.

Mount Annan Botanic Garden

Australian native plants

What type of soil do gum trees grow in?
Gum trees grow all over Australia in many different types of soil. They grow best in deep, well-drained soil. Don’t plant them too close to buildings.

What is the most endangered plant in Australia?
Many plants in Australia are rare or endangered and some are extinct. There is an Australian rainforest tree in our Gardens called a Whitewood that is only known by a couple of trees. An example of a rare Australian tree is the Wollemi Pine.

Why are individual eucalypt species such as the Sydney Blue Gum confined to specific localities?
The eucalypts are an extremely successful group of plants in Australia today, with over 800 species known. Individual species have evolved adaptations to virtually all habitats, and the genus ranges across the entire continent. The great radiation in the evolution of today’s eucalypts is partly a response to different habitat conditions, and individual species are frequently adapted to a very narrow set of habitat conditions. Because the species are adapted to such narrow requirements, competition is extreme, and each species is consequently restricted to its own narrowly defined habitat.

What plants could adapt to the Sydney coastal area?
The soils in the Sydney area are sandy and porous, meaning they don’t hold much water and they are poor in some minerals like nitrogen and phosphorus. Much of the area is also exposed to salt spray and winds which can dry and damage plants. Plants adapted to the Sydney coastal area include wattles, banksias, tea trees, bottlebrushes, grevilleas, eucalypts, hakeas and she-oaks.

Are there any rare plants in Sydney?
There are between 50 and 55 rare plants in the Sydney and Penrith area. Most of the plants are threatened because of the destruction of their habitat (the place where they grown in nature) for houses and factories, and roads and the illegal dumping of house and garden rubbish in the bush.

What are the best native plants to use on the coast as ground covers?
Check what is growing in your area. A couple of good native ground covers that grow in coastal regions are Guinea Flower Hibbertia scandens and Dusky Coral-pea or Running Postman Kennedia rubicundra.

We have several gardening fact sheets on growing native plants.

Syzygium paniculatum

Plant relationships

What is the relationship between Grevillea and close relations, if any, in other parts of the world?
Grevillea includes about 350 species and not all of these are restricted to Australia. Six species are native to other countries and of these, four do not occur in Australia. Three of these, Grevillia meisneri, Grevillea gillivrayi, and Grevillea exul occur only in New Caledonia, while Grevillea papuana occurs only in New Guinea. The closest relatives of Grevillea are Hakea and Finschia but we are still unsure whether these are really separate genera. More distant relatives of Grevillea include Australian genera like Banksia, Telopea (waratahs) and Macadamia, as well as genera native to other continents in the Southern Hemisphere, such as Embothrium in South America and Brabejum in Africa.

What are the reasons for the relationships between Grevillea and its relatives in South America and Africa?
Grevillea, like nearly all other genera in the Proteaceae, is restricted to Gondwanic continents and continental fragments. These are pieces of land that once were connected to form the ancient supercontinent of Gondwana. The Australian plate and New Caledonia, the Gondwanic fragments to which Grevillea is now restricted, were part of the same land mass until about 70 million years ago when they rifted apart. The ancestors of Grevillea are thought to have been separated by continental drift and that is why the genus now occurs on separate landmasses.

Does a fossil have to be an extinct animal or animal, or not?
Fossils take a long time to form. Often fossils are of plants and animals that no longer exist on earth. However a fossil doesn’t have to be an extinct plant or animal. Fore example some shells have existed in very stable environments in the ocean and do not appear to have changed in millions of years. Sometimes it is easy to recognise that more recently formed fossil leaves are obviously still-existing species.

Mount Annan Botanic Garden


How did the climatic changes due to continental drift affect Australia’s flora and fauna?
Australia’s climate has changed markedly due to continental drift during the Tertiary period (the last 65 million years). The climate was uniformly warm and wet until the Miocene (up to about 30 million years ago). It then changed to be more like the present-day climate: much drier overall, and highly erratic. The drier climate led to a large-scale reduction in forest cover in Australia, with rainforests formerly covering most of the continent becoming reduced to small relics in the ranges along the east coast. Species adapted to the rainforest habitat were greatly depleted in both range and numbers, and many became extinct. At the same time, certain groups proved to be more resilient, and evolved adaptations to survive the new drought conditions. These groups evolved and radiated into the drier areas, in many cases developing wide diversity - examples include Eucalyptus, Acacia, Melaleuca, Grevillea, and macropods (kangaroos and their relatives).

How did the break-up of Gondwana affect the distribution of the flora and fauna present in Australia?
The break-up of Gondwana into several smaller continents had the initial effect of dividing the once uniform biota between the different new continents and isolating segments of once uniform gene pools. These isolated segments were then able to drift genetically and slowly evolve new species and entire new biotas. A later change in climate caused dramatic changes in the nature of the biota and forced evolution and adaptation at a faster pace, giving each fragment of Gondwana a unique and different biota. Another even later effect was to raft the isolated biotas to different localities and into contact with new and different biotas. This allowed migration both to and from Australia, and introduced new biotic elements from the older Gondwanan and Laurasian landmasses of south-eastern Asia.

What evidence is there for the evolution of eucalypts in Australia?
Evidence that the eucalypts evolved in Australia is mainly circumstantial. The majority of species now occur in Australia, with only 12 of the 800 or so known species occurring outside of Australia. In addition, the most widely separated branches of the family tree all occur within Australia, whereas only some lineages extend beyond Australia. All of the latter clearly have roots in Australia, and most probably represent relatively recent emigrants from Australia. The fossil record does not assist greatly, with limited preservation of eucalypts.

Have Angophoras and eucalypts evolved from a common ancestor?
The eucalypts and Angophoras have evolved from a common ancestor. The nearest relatives of this group are a small group of rainforest genera, one from New Caledonia, one from New Guinea, and two from northern Australia. All occurrences are associated with fragments of the ancient southern supercontinent Gondwana, and it has been suggested that the eucalypts evolved in the Australasian fragment of Gondwana. Early eucalypts were probably also rainforest trees.

Since the cycads are ancient trees and they live to be 1000 years or more, why aren’t they dominating the tropical forest regions of the world?
No-one has come up with a good way to date cycads, which don’t have annual growth rings. So we don’t know how old the oldest individual plants are – several hundred years is the current guess. As a group, the cycads have certainly been around for a long time – at least 200 million years judging from the fossils that have been found – and they were once much more common than they are now. Most cycads grow slowly, which is why they have not been able to compete very successfully with the faster-growing flowering plants such as tropical trees and lianas. In fact, in tropical areas cycads mostly grow in more open areas, often on rather dry hillsides, where they are not shaded out by trees. Where they grow as understorey plants these particular species rarely form very tall trunks.

Mount Tomah Botanic Garden


What plant life lives in Antarctica?
Antarctica is about twice the size of Australia. You can find plant life on only about 2% of this area. This is because of rapid temperature changes, strong drying winds, irregular water and nutrient supplies and continual soil movement due to freezing and thawing. Plants can be found in the dry valleys of Victoria Land, the Antarctic Peninsula, in small areas where the snow melts in summer, and in freshwater lakes. On exposed rocks where it is very dry you would find lichens (there are about 350 species) and in the wetter areas, mosses (about 70 species in total) and liverworts. In summer you might see pink snow - caused by pink algae surviving there. Only two flowering plants grow south of 60 degrees south - a hair grass Deschampsia antarctica and pearlwort Colobenthos quitensis. These live in small clumps near the west coast of the Antarctic Peninsula. The plants need nutrients and tend to grow around nesting birds. Seaweeds can also be found in the surrounding waters.

Is there anything is the environment that is destroying or threatening the plant life in Antarctica?
Yes - people have been living in Antarctica on and off for over 50 years. They arrive in ships or in planes, build airports and buildings, establish fuel dumps, eat food, make waste, etc. All these activities have an effect on the plant life.

Are there any plants in Antarctica essential for research purposes or indicators of change that might be occurring in the environment?
Tests by biologists on plants help us to learn how these plants are suited to their environment, e.g. lichens have been frozen at temperatures as low as -198 degrees C and have revived with moisture 15 years later. Biologists measure the size of plant populations. A change in population could indicate a change in the speed of the ice melting. Because Antarctica has such an enormous area of ice, a change in the amount of melt will affect the sea level, sea currents and weather around the world.


Dicksonia antarctica


How many rainforest foods do we produce in Australia?
The main commercial food from an Australian rainforest plant is the Macadamia or bush nut, which ironically was commercially developed in Hawaii.

Are there any plants in Australian rainforests which produce seeds that are poisonous?
The fruits of the Black Bean or Moreton Bay Chestnut are poisonous. The were eaten by Aborigines, but only after complex treatment. Cycads (not always rainforest dwelling) are also very poisonous.

Where are most of the foods founds in the rainforest?
From all parts of the rainforest – the canopy, understorey and from the leaf litter on the rainforest floor. Indigenous people used rainforest as a source of food and shelter and for raw materials. They also hunted animals in the rainforest.

What foods do we eat today which originated from rainforests?
Many foods originated from rainforests, including bananas, pineapples and avocadoes.

Are there any medicines that come from rainforest plants?
Probably one of the most famous examples is the drug quinone, which was originally extracted from the bark of the Cinchona tree of Peru, and is used to treat malaria. Traditionally rainforest plants have been an important source of medicines – examples include emetine (used for amoebic dysentery), reserpine (for hypertension), picrotoxin (to relieve convulsions), tubocurarine (a muscle relaxant during surgery). There are probably many more valuable products yet to be discovered. Once isolated, drugs would normally be produced synthetically.

Which is the world’s biggest rainforest?
The biggest rainforests in the world are found in Indonesia and New Guinea.

Click here to find out more about rainforests.

Mount Tomah Botanic Garden

Plant names & classification

How do plants get their names?
Traditionally plants have had common names, like ‘Christmas Bush’ which refers to a bush that flowers at Christmas time. This can be confusing as more than one bush may flower at Christmas time and common names may vary from place to place.  Plants are given scientific names to solve this problem of having different names in different locations. The scientific name consists of a genus (like a surname) and a species name (like a Christian or given name), and is established when the plant is first described by a botanist. Latin or Greek are used as these are ‘universal’ languages. To be accepted by the scientific community the name has to be published in a scientific magazine, and a brief description given in Latin. Names can change as scientists obtain more information, and there are special rules for changing or not changing names.

What is the basis for plant classification?
Plants are classified into groups according to similarities and differences, in an attempt to establish their relationships. Traditionally plant classification has been based on external (visible) features, like leaf form and floral parts. More recently chemical methods have been used, from chromosome counting to DNA ‘fingerprinting’.

How are names like ‘Myrtaceae’ chosen?
‘Myrtaceae’ is the name of a plant family as can be seen by the fact that it ends with ‘eae’, and it is the name of the ‘Myrtle’ family, given because its members resembled the myrtle of the Northern Hemisphere. Genus and species names are constructed botanists who describe those plants for the first time. The names are usually from Latin or Greek and are descriptive. In the case of species they may describe a feature (e.g. long flowers) or a location, or they may be named after the person who found the plant.

Are there any plants that are hard to classify?
Classification is to do with establishing groups of convenience, and the plants have not read the books! Plants are living things and life is a continuum, so there will always be grey areas of overlap in any system of classification. Some plants (the ones in the middle of a group if you like) will always be easy to classify, whereas those plants at the edge (in overlap regions) are the ones that cause the problems. New technologies like DNA ‘fingerprinting’ and cladistic analysis have been an exciting recent development in the field of taxonomy (classification).

Click here to find out more about plant names & classification.

Mount Annan Botanic Garden

Careers in botany

How much training does it take to become a botanist?
To be a botanist it is important to study science up to the end of high school – preferably biology and chemistry in years 11 and 12. After high school it is then necessary to study science for at least three years at university, majoring in botany. At university it is necessary to decide which area in botany you want to specialise in for post-graduate study. These days an aspiring botanist would be advised to keep on studying at university for as long as possible - most botanists today have a Masters degree or a PhD (Doctor of Philosophy degree in science).

What degree does a botanist have?
The basis degree to become a botanist is a bachelor of science (BSc) degree.

How long does it take to find out all about plants?
A few hundred years ago when there was less scientific knowledge a person could know virtually everything there was to know about a wide range of things. These days there is so much knowledge that a scientist has to specialise. The science of botany is now broken down into a range of specialist subject areas, e.g. phycologist, plant physiologist, etc. The study of any field of botany continues throughout a lifetime, and is never really finished, as one person can never know everything there is to know about plants. And apart from that there are still many things we do not know yet.

How do you find out so much information about plants?
Scientific information, like in any other subject, is the result of the accumulated work of many people over a long period of time. People who have brought all this knowledge together then write the reference books on the various subjects. Books are then used as sources of information to teach children at school and student at university. Book are still used by scientists to check on information. The most up-to-date information is to be found in scientific ‘papers’ - articles about special topics of research - that are published in scientific journals (magazines formed especially to publish scientific papers). More and more information is becoming available from the Internet.

What is it like to be a scientist?
Our scientists study plants and give them names. The good part of the job is that you can spend time looking for plants in interesting places. It is very exciting to discover a new type of plant. Of course, it isn’t always exciting - you also have to look after collections of dried plants. A lot of work has to be done to check that no on else in the world has previously discovered a particular plant. One of the hardest things about being a scientist is that you have to worry about obtaining money to do research where there is not always an obvious economic benefit to that research.

Click here to find out about careers & jobs at the Royal Botanic Gardens & Domain Trust.

Collecting waterplants