01. Ghost Orchid – Most Devious Plant
Name: Epipogium aphyllum.
Ability: Cheating a fungus.
The natural world as we know it is built on partnerships. But in all societies there are cheats, and plants are no exception. Most green plants would be unable to exist without the help of fungi, which provide them with food-exchange partnerships. In fact, the invasion of the land by plants – algae – was probably only made possible by such partnerships. It has even been suggested that early land plants developed roots just so they could join forces with the fungal roots, or hyphae. Most plants are proper partners, giving the carbohydrates they manufacture with their chlorophyll.
Some, notably orchids, have such a close partnership that they don’t even bother to produce proper food packages to accompany their embryos into the world, instead relying on fungi in the soil to provide the food needed for germination and early growth. This allows an orchid to produce light-weight, microscopic seeds – millions of them.
Some orchids, however, have become cheats: they use fungi that have partnerships with trees, and they never give anything in exchange. Via fungal hyphae, these orchid vampires tap into the trees, siphoning off nutrients. The give-away is often the fact that they have stopped producing chlorophyll and so aren’t green but a rather sickly pinkish cream, like the ghost orchid, or brown, like the bird’s-nest orchid. Some, such as western coralroot, are blood red or even purple. The drawback is that, without the fungus, the orchid will die. And one day a fungus might just evolve a way to get its own back.
02. Castor Bean – Deadliest Plant
Name: Ricinus communis.
Ability: Producing the deadly poison ricin.
The castor bean plant produces possibly the most deadly plant toxin, 6,000 times more deadly than cyanide, but it has also been known for thousands of years as a wonder plant. The secret and the poison both lie in the seed. More than 50 per cent of it comprises a rich oil, but to protect it from being eaten is ricin, a protein toxic to almost all animals (lesser quantities of ricin occur in the leaves). The poison, once ingested, inactivates the key protein-making elements of a cell without which it can’t maintain itself and dies.
For humans, death is prolonged, ending in convulsions and failure of the liver and other organs. There is no known antidote. The most usual cause of poisoning comes from accidentally eating seeds, but ricin can be administered in aerosol form, in food or water, or injected, as in the famous case of a dissident Bulgarian journalist. While waiting at a bus stop at Waterloo station in London, in 1978, Georgi Markov was murdered by being stabbed with an umbrella that injected a pellet containing ricin. Widely available and easily produced, ricin could be used for biological warfare.
It is equally easy to extract the seed’s valuable oil, however, which has been used for at least 4,000 years as a lamp oil and soap and also as medicine for a huge array of ailments. Today its uses include high-grade lubricants, textile dyes, printing ink, waxes, polishes, candles and crayons. In the future, its array of protective chemicals may even provide a cure for tumors.
03. Gympie-gympie Stinging Tree – Most Painful Tree
Name: Dendrocnide moroides.
Ability: Defending itself with toxic chemicals.
Of course, any tree could fall on you, and plenty of trees are poisonous to eat, but this aside, the trees that cause the most excruciating pain are ones that you just brush against. These are the stinging trees that are found in several parts of the world but are most persistently painful in that land of advanced toxins, Australia. Here are six Dendrocnide species, two of which – the northern shiny-leaf stinging tree and the southern giant stinging tree – are large, tree-like trees, and four of which are more like shrubs. Of the six, the worst agony is said to be inflicted by a shrub, the gympie-gympie, but they all hurt a lot.
What looks at first like a layer of fur on all parts except the roots is really a mass of tiny glass (silicon) fibres containing toxic chemicals. Just a brush against a tree results in the skin being impaled with a scattering of fibres, which act like hypodermic needles and are all but impossible to extract (Australian first-aid kits sometimes include wax hair-removal strips). The poison causes burning, itching, swelling and sometimes blistering that is said to be at its most unbearable soon after contact but can keep causing pain for years. The fibres can penetrate most clothing, and sometimes airborne ones can be inhaled. Oddly, the stings don’t affect all animals. Insects and even some native mammals actually eat the leaves. The ones that suffer tend to be introductions to Australia, such as dogs, horses and humans.
04. Amorphophallus Titanum – Smelliest Plant
Name: Titan arum, corpse flower, or devil’s tongue.
ABILITY: pumping out the smell of decomposing flesh.
What smells bad to us often doesn’t bother other animals. In fact, the scent of the foul-smelling titan arum – the tallest and probably heaviest of flowering structures – is positively attractive to carrion beetles and bees. Whether its smell is the worst, to us, has still to be tested (there are other contenders for this, including the even bigger giant titan, A. gigas). But the titan arum produces a sufficiently awful smell to make people faint.
The “flower”, or inflorescence, comprises a vase-shaped spathe (petal-like leaf) at least 1.2 m (4 ft) tall, which grows rapidly from a gigantic tuber weighing up to 80 kg (177 lb). Out of this rises a spadix, a spike with thousands of tiny flowers more than 2.4 m (8 ft) tall, so strange it gives the arum its scientific name: “huge deformed penis”. The upper part of the spike produces the smell, and to make it travel further, the spadix generates heat and may steam at night as it pulses its fragrance of ammonia, rotting flesh and bad eggs for up to eight hours at a time.
This attracts pollinating, carrion-loving insects, but few people have observed the pollination, probably because the plant flowers only every 3–10 years and then for just two days. Once the flower dies and hornbills have dispersed its seeds, it’s replaced by a titanic leaf up to 6 m (20 ft) tall, which makes the food so that, one day, the tuber can grow another stinking flower.
05. Venus Flytrap – Fastest-moving Plant
Name: Dionaea muscipula.
Ability: Grabbing insects at a speed of a fraction of a second.
Plants may have limitations on movement, and they don’t have muscle power, but there are ways round that. The Venus flytrap uses elasticity to set its two-lobed, snap-jaw trap. The animals it kills provide the nitrogen and other essential minerals it needs to stay healthy and set seed in its nutrient-poor, water-logged and acidic habitat.
The upper side of each lobe is stretched tauter than the underside (its cells elongate under water pressure) and the lobe curves back by tension, like a bow. It lures insects with nectar, which it produces via glands along the rims of the lobes. The trap is released when several of the six or so sensitive trigger hairs sense movement and send chemical-electric signals that cause water transfer between cells, releasing the tension. The result is an instantaneous shutting of the trap.
The Venus flytrap is also to be admired for another talent. This weird plant can ‘decide’ if something inanimate is in the trap, by counting whether there are two or more stimulations of the hairs – any fewer and the trap won’t work. The lobes tighten to form a seal as enzymes are released (with antiseptic to deter bacteria and fungi) and then the prey is digested. A week or so later, the trap is ready to kill again.
Only bladderworts rival the flytrap for speed. They catch tiny creatures under water with bladder traps, closing the seals of their traps in a similarly tiny fraction of a second.
06. Tortoise-shell Bamboo – Fastest-growing Plant
Name: Moso, Phyllostachys edulis.
Ability: growing literally centimeters (even inches) an hour.
Bamboos are strange plants. For a start, they are giant, woody grasses. Most of the 1,250 or so species do all their growing in early life. Once mature, a bamboo doesn’t grow any taller, no matter how long it lives (and some survive for more than 100 years), preferring instead to send up more shoots. This means a stand of clumping bamboo, while getting no taller, can become impenetrably thick.
Flowering is eccentric, too. Many species flower only once in their lives when aged between seven and 120, and then die. And that means that every single plant of a particular species may set seed at exactly the same time and die at the same time. (This is a special problem for giant pandas, which eat virtually nothing but bamboo and face general famine every 30–80 years, when the local bamboo species flowers.)
Bamboo is also hugely important to us (there are more than 1,500 documented uses for it), and up to 40 per cent of the world’s population depends on it. As for tortoise-shell bamboo, it invests a huge amount of energy in seed production but may survive flowering and is widely grown as a crop. It’s one of the tallest giant bamboos and probably the fastest growing. One shoot is recorded as putting on a meter of growth in a single day – that’s 4 cm (1.6 in) an hour – and another grew 20 m (65 ft 6 in) in eight weeks. It really is grass that you could watch grow.
07. Honey Fungus – Most gargantuan of growths
Name: Shoestring rot, Armillaria ostoyae.
Size: Covers more than 890 hectares (2,198 acres).
All the humongous fungi records are held by underground clone colonies of species of honey fungus. The success of honey fungus lies with its ‘shoestrings’, or rhizomorphs – parallel hyphae (root-like extensions), covered in a tough, dark rind. These shoestrings travel huge distances in search of food – vulnerable trees or dead wood – and pass back nutrients to the main mass of hyphae, called a thallus. They penetrate the bark of a living tree, often a young one, and siphon off water and nutrients from the sapwood. If the tree doesn’t defend itself properly, the rhizomorphs spread to the roots and effectively strangle the tree, extracting nutrients from the dying wood. Over the years, new colonies form, all clones of the original organism.
The largest-known mass of honey fungus, identified by DNA fingerprinting, is an Armillaria ostoyae clone in Oregon, 5 km (3 miles) across in some places and estimated to be at least 2,400 years old (possibly twice that age). In autumn, it sends up great masses of fruiting bodies, though the individual mushrooms are small by comparison with those of long-lived fruiting bodies of species such as the artist’s fungus Ganoderma applanatum. Even larger honey fungus clones may exist in the huge conifer forests of Eurasia (Armillana particularly likes certain conifers). Though the fungus might seem monstrous, it is part of a forest recycling system, creating spaces for new plants to grow and adding organic matter to the soil that provides nutrients for the trees.
08. The Stratosphere Giant – Tallest Living Thing
Name: California redwood, Sequoia sempervirens.
Height: 112.8m (370ft 2in).
The Stratosphere Giant may now be the tallest tree in the world – and, the tallest living organism. But the tallest ever reliably reported – the Cornthwaite Tree, a huge mountain ash in Victoria, Australia – was measured after it had been felled in 1855 as 114 m (374 ft). The tallest mountain ash today, growing in Tasmania, is a relatively short 97 m (318 ft 3 in). This means that all the tallest trees now are California redwoods, and there are about two dozen taller than 110 m (360 ft).
Redwoods have been extensively logged, and so it’s very likely that there have been taller ones than these in the past. But how much taller? According to calculations made in 2004, taking into account such factors as the pull of gravity and the limits of water friction, it’s possible for a California redwood to grow to between 122 m and 130 m (400–426 ft).
So what goes on 50 or 60 storeys up a tree? For one thing, these trees sprout whole new trees, known as reiterated trunks. One redwood studied had a whole forest in its crown – 209 reiterated trunks. Most of them were fairly small, but the largest was 2.6 m (8.5 ft) in diameter and 40 m (131 ft) tall. Deep soil had also accumulated up there, in crotches and on large branches, and growing out of it were ferns, shrubs and other trees, not necessarily redwoods. There were also plenty of insects and earthworms, molluscs and even a sizeable population of salamanders.
09. King’s Holly Lomatia Tasmanica – Oldest living clone
Name: Lomatia tasmanica.
Age: More than 43,600 years old.
This remarkable shrub was discovered around 70 years ago by self-taught naturalist Deny King, while panning for tin on a mountain range in south-west Tasmania. But that area was later burnt, and the plant was never seen again. Then, in 1965, King found another population in a cool, rainforest site on a range further east. It was confirmed as a new species, a member of the Proteaceae family (with its closest relative in Chile, hinting at the time when Australia and South America were joined together), and was named in King’s honor.
The plant is sterile, being genetically triploid (having three pairs of chromosomes instead of two). Since it cannot reproduce sexually, its attractive red flowers never set seed, and it can regenerate only by shooting from root suckers. This also means that all 600 or so plants in the population are genetically identical clones.
Even more extraordinary, fossil leaves of the species collected in the same region and visually identical to living leaves have been radiocarbon-dated as at least 43,600 years old. Because of this and because it reproduces clonally, biologists believe the living King’s holly plant and the fossil to be, for all practical purposes, the same plant. This makes the species the oldest-known clone, beating the creosote bush (at 11,700 years) and the previous record-holder, the North American huckleberry (at about 12,000 years). It was alive when Homo sapiens and Neanderthal man existed together, but tragically, this ancient survivor is now threatened with extinction.
10. Quaking Aspen – Heaviest Living Thing
Name: American aspen, Populus tremuloides
Size: 6,000 tonnes (5,900 tons)
This is one huge tree complex – a giant stand of genetically identical tree trunks connected by a common root system and weighing thousands of tonnes – called Pando, or ‘I spread’, in Latin. Though the individual trees, or ramets, are comparatively short lived, there are at least 47,000 of them, all males, and the clone itself is at least 10,000 years old. It may even be a lot, lot older. And though the ramets are comparatively slender and seldom get to be very tall, the area the tree complex covers is at least 43 hectares (106 acres).
The quaking aspen can reproduce in a normal, sexual way, producing seeds. But if conditions are not good for seed germination or if the aspen is damaged by fire or an avalanche, it opts for fast, vegetative reproduction, throwing out new suckers to replace fallen trees and continue the spread of the organism. In fact, being partially fire-proof, it thrives on periodic fires, which kill off competing trees.
A mature root system like that of the giant clone is also capable of putting out nearly half a million shoots a hectare (nearly a quarter of a million an acre), and since aspen shoots can grow a meter a season, it can out-compete other trees. As a result, the quaking aspen successfully colonized North America in the wake of the last ice age and is now the most widely distributed tree on the continent and the second only to juniper as the most widespread tree in the world.
11. Rafflesia Arnoldii – Largest Flower
Size: Up to 0.9m (3ft) in diameter, 11kg (25lb)
The flower is all you’ll ever see of a Rafflesia, because the rest of this intriguing plant is comprised of just threads inside a tropical vine. It is a slow-growing parasite, totally dependent on Tetastigma vines, from which it draws nutrients.
It is very rare for a rafflesia bud to emerge from its host on the forest floor, and about nine months pass before it swells to the point when it literally bursts open. Its five fleshy lobes (red sepals) curl back to release a putrid stench like rotting meat and reveal the huge, open-topped dome that houses the reproductive parts (which can be either female or male). The smell attracts carrionloving beetles and flies. As the pollinators don’t fly far, flowers need to be nearby and flowering synchronized so pollen can be moved from male to female flowers within just a few days. How this happens is a mystery. Another mystery is how any of its thousands of tiny seeds land on a vine, though it’s possible they get there via the dung of the tree shrews and squirrels that eat the fruit.
Somehow, a seed penetrates the stem and starts growing. But it will be years before it buds. Rafflesia’s scientific name commemorates two famous 19th-century plant and animal collectors – Sir Stanford Raffles, founder of Singapore, and botanist Joseph Arnold. Sadly, as its host is disappearing with its shrinking rainforest home, Rafflesia itself is fast becoming history.
12. Welwitschia – Oldest leaves
Name: Tweeblarkanniedood (two-leaf-cannot-die), Welwitschia mirabilis.
Age: Can live to be more than 1,500 years old.
This plant is essentially just a pair of leaves on a short, bowl-like stem. Individuals get to be very, very old. Their strap-like leaves grow and grow and don’t drop off. But they do get thrashed by the wind and so are never longer than about 6 m (20 ft) – rather than the 200 m (656 ft) they could grow to be – and are sometimes terribly split and tangled.
Welwitschia usually grows near enough to the coast to make use of the fog that rolls in from the Atlantic Ocean at night. Moisture condenses on the leaves and is both channeled down to the root and taken in through the breathing pores, or stomates. Sometimes welwitschia conserves water with a special method of photosynthesis (the way plants make food). The leaves open their stomates and take in carbon dioxide, not in the day, as do most other plants, but at night, when temperatures are coolest and they won’t lose water through transpiration (evaporation through the stomates). They then store the carbon atoms as special acids until the sun’s up and they can photosynthesize – using the light to synthesize the carbon into carbohydrates.
Instead of flowers, welwitschia produces cones like other gymnosperms (conifers, ginkgoes, cycads and seed ferns). These are either male ones with pollen or female ones that form the seeds. Both produce a sticky fluid – in the case of females, to capture pollen, and in the case of males, to attract insects to disperse pollen – a combination of characteristics of both flowering and non-flowering plants.
13. Ginkgo – Oldest Surviving Seed Plant
Name: Maidenhair tree, Ginkgo biloba.
Age: The genus dates back 280 million years.
This tree is the ultimate survivor. When Hiroshima was bombed in August 1945, virtually every plant in the city was destroyed, including a particular ginkgo tree, which was burnt and irradiated. In the spring of 1946, the remains of that tree produced one sprout. Today it’s a perfectly healthy tree growing in the grounds of a temple 1 km (0.6 miles) from the center of the blast.
Ginkgoes pre-date lots of things – flowers, for instance. When ginkgoes first appeared on Earth, 280 million years ago, there were no angiosperms – no plants that produced flowers and encased their seeds in fruit. In fact, as a member of the Ginkgoaceae family – the last survivor – Ginkgo biloba is somewhere between the primeval cycads, conifers and primitive ferns and the first flowering plants. This species has held on through Earth-shaking volcanic cataclysms, asteroid collisions and the general environmental change that caused all the plants that were the ginkgo’s early contemporaries to die out or evolve into something else.
Its real problems were ice ages. It was frozen out of North America 7 million years ago and Europe 3 million years ago. But ice never reached parts of south-eastern China, and that was where they enlisted the help of a very newly evolved species – Homo sapiens. Trees were found by the ancient Chinese and cultivated in their temple gardens. Now, though probably extinct in the wild, they thrive in cities all over the world because of their resistance to air pollution and disease.
14. Banyan Tree – Biggest canopy
Name: Barh, Ficus benghalensis.
Size: The largest has a diameter of 420m (1,378ft).
In AD 70, Pliny the Elder, one of the first great natural historians, wrote, ‘There is in India a tree whose property it is to plant itself. It spreads out mighty arms to the earth …’. He was writing about adventitious roots, which are the secret of the banyan’s reputation as the world’s greatest shade-giving tree.
Like many of the nearly 2,000 other species of fig, the banyan can send roots down from its branches. These create pillars that support the branches as they continue to spread. The carefully tended banyan in the Indian Botanic Garden, Calcutta, with its 2,800 prop roots, is the largest known banyan. All over southern Asia, the trees are cared for and used as gathering places – as markets or schools or for village assemblies – and, indeed, the name comes from banias, or merchants, because that was where English traders did business with the locals.
Other species of fig famous for their adventitious roots are the ‘stranglers’, which germinate from seeds in another tree’s canopy and send roots coiling down the trunk. Eventually, the fig crushes the host to death, leaving just a tall fig tree in its place. The success of fig trees is partly the result of the adaptability of their roots, but these aren’t always adventitious. When growing like normal trees, they take the soil as it comes: thin, and the roots spread out; deep, and they go straight down. The deepest ever recorded are those of a fig in South Africa, measuring 120 m (400 ft).
15. Giant Puffball – Greatest Number of Spores
Name: Calvatia gigantea.
Ability: Producing up to 20 trillion spores from just one fruiting body.
Most large fungi spread themselves by releasing into the air multitudes of microscopic spores from special fruiting bodies – mushrooms and toadstools – that grow above ground. Some use animals, water or even plants to help move the spores, but most rely on the wind to blow them away, sometimes over huge distances. The spores are usually released by the use of special turgid cells, which means that most fruiting bodies can’t risk drying out. These mushrooms and toadstools therefore usually grow when it’s damp.
The giant puffball, however, doesn’t rain spores from a multitude of downward-facing pores or gills in the usual way. Instead, it bears them internally, keeping them nicely humid, and releases them gradually. If conditions are moist enough, it matures in just a week or so, swelling to huge proportions–some-times to more than a meter. It then begins to split open, aided by the odd animal knock and abrasion, to release over weeks or even months billions or trillions of spores into the wind. This isn’t considered a very efficient method of dispersal, as most spores will neither travel far nor survive, which is why it produces so many of them. But then the job is done if just a few spores settle and ‘germinate’ in favorable (nitrogen-rich) nearby pastures. It’s also a good thing that all the spores don’t grow into puffballs. If they did, in just a couple of generations, the puffballs would have a total volume many times that of the Earth.
16. Coco-de-mer – Biggest Seed
Name: Seychelles nut, Lodoicea maldivica.
Size: The fruit can up to 48cm (19in) across and weigh more than 22kg (48lb).
These so-called double coconuts were impressing people long before the islands they came from were ever discovered. They used to wash up on beaches around the Indian Ocean, and sailors would pick them up at sea. Before the discovery of the Seychelles in 1743, the general belief was that they were the fruit of a gigantic tree growing on the ocean floor – hence coco-de-mer or ‘nut-of-the-sea’. Then, for a time, they were thought to come from the Maldives, which accounts for the scientific species name. Another theory was that they were from the Tree of Knowledge in the Garden of Eden, and the reason for that one is pretty obvious: the striking resemblance to a woman from waist to mid-thigh. Naturally, they were also thought to be aphrodisiacs.
The reality is pretty fantastic, too. The coco-de-mer palm is incredibly slow growing. The first leaf starts to appear nine months after germination begins, and the first flower can take another 60 years (there are male and female palms). The two-lobed fruit may take up to ten years to ripen, and it may be a century before the tree reaches its full growth of about 30m (100ft). The tree’s leaves, when they’ve finally grown, can be 6m (20ft) long. As for the nuts, they are edible and are a lot like coconut. It’s not likely, though, that anyone would be eating them nowadays. The tree is close to extinction, and the nuts, which are sometimes sold to botanical gardens, can cost as much as £800 ($1,500) each.
17. Pitcher Plants – Slipperiest plant
Name: Nepenthes species
Ability: Catching prey in slippery, deadly pitchers.
There are many different species of pitcher plant, but all are insect-traps with the slipperiest of sides, providing extra nitrogen (from insect corpses) to help the plants flower and set seed. Among the most sophisticated are the leaves of vine-like Nepenthes. Each of these pitfall traps has an “umbrella” lid and a base partly filled with a soup of digestive enzymes. The lure may be color (usually red), smell (nectar or, later, rotting corpses) or tasty hairs. When an insect lands on the rim, it slips into the deadly broth, possibly intoxicated by narcotic nectar.
Slipperiness is achieved in two ways, perhaps depending on what insects are likely to be attracted (walking insects if the Nepenthes is on the ground or flying insects if it is up in the tree canopy). The inner walls are usually impossible to climb, being covered with slippery waxy platelets. Others go a stage further and have a surface that attracts a film of water which aquaplanes the insects to their death. Some also use trickery. When their pitchers are dry, ants are lured by the nectar, and don’t slip, and so go and tell more ants about the find. If the surface is wet when they return, they all fall in.
Another of the Nepenthes species is in partnership with an ant that has specialized feet, allowing it to get in and out of the pitcher to retrieve corpses. It eats these and drops the remains and its faeces into the pitcher, so speeding up the release of nitrogen for its predatory host to ingest.