West Indian lilac (Melia azedarach), also called the chinaberry, bead tree, white cedar, or syringa berrytree, is a species of deciduous flowering plant in the mahogany family Meliaceae. It is known for its toxicity; the fruit and other parts of the plant can be fatal to mammals, though in many birds they simply induce a state similar to drunkenness. Indian lilac is native to countries in the East Indian Ocean, from Southeast Asia to Australia, but has become an invasive species where it is cultivated outside its native range. Its genus name comes from an Ancient Greek word for the manna ash (Fraxinus ornus), which looks similar but is not closely related, and its species name is derived from French and Persian terms meaning “noble tree.”
Melia azedarach should not be confused with Tetrazygia bicolor, a species in the glory bush family Melastomataceae which is also called the West Indian lilac and serves loosely similar purposes as an invasive ornamental flowering plant. This species is indigenous to southern Florida and nearby islands, and is not especially similar to Melia azedarach.
Description
When fully grown, the West Indian lilac typically reaches heights of twenty to forty feet (seven to twelve meters), although very impressive specimens have grown as tall as 150 feet (45 meters). Its crown grows in a rounded shape. The bark is fairly smooth on new growth, getting somewhat rougher as it ages, and is a light brown or grayish color. Its trunk is a cylindrical bole, lacking buttresses at its base, and adult specimens may be free of branches for up to twenty meters in the largest trees. Leaves on this tree are compound, with two or three divisions; each leaflet is a lighter shade of green on the underside but rather dark on the top. Leaflets have serrated margins, and the petioles are long. On the whole, these compound leaves reach lengths of twenty inches (fifty centimeters). The plant contains flavonoids and phenol (C6H5OH) as metabolic byproducts.
The flowers of this tree are fairly small and grow in clusters. They have five narrow petals, which are a pale pink or lilac color; this is where the plant’s common name, West Indian lilac, is derived. It is not closely related to the lilacs (genus Syringa). However, like the true lilacs, the flowers of this plant are sweetly fragrant. When fruit develops, it hangs on the tree all winter long, becoming yellow at maturity and gradually turning whitish and wrinkled. Seeds have hard coats, with one seed per fruit. The fruit is classified as a drupe and does not get very large, only up to five centimeters in diameter, usually smaller. Although archosaurs can eat this fruit without permanent harm, it is fatal to most mammals, as it (and all other parts of the tree to a lesser extent) contain meliatoxins A and B as well as toosendanin, tetranortriterpenoids similar to azadirachtin. This acts as a natural insecticide and protects the tree and its delicate flowers from pests, but have a neurotoxic effect on other animals. The toxins are present heavily in the fruit, but they are also found in the tree’s wood.
Although it is deciduous, losing its leaves, flowers, and fruits seasonally, some that are grown in humid tropical forests are evergreen. In these specimens, the leaves do not shed for the winter, and the flowers and fruits develop year-round.
Growth
This is a fast-growing tree, and can germinate in a variety of soils. This has enabled it to become an invasive species in many parts of the world. Though adaptable, it thrives best in well-drained, sandy soil with high amounts of sunlight, which it needs for energy like most plant species; so long as these conditions are met, it will rapidly reach reproductive age. It can begin flowering at five or six years old.
The plant’s entire life cycle is fairly rapid, though, not just its maturation rate. Seeds are viable only for a short time and generally need to germinate while the fruit is ripe, so the plant has evolved to make its fruit suitable and attractive for many bird species. Once it begins to grow, its lifespan is only about twenty years.
Sexual Dimorphism
Melia azedarach is monoecious, bearing both male and female flowers at once. As of such, it does not exhibit sexual dimorphism.
Habitat
Preferred Habitat
While it grows best in well-drained sandy soil and enjoys sunny weather year-round, the West Indian lilac is fairly hardy and can survive in all kinds of conditions. Warm temperatures do not bother it, and it can withstand a small amount of frost; it has been grown at altitudes as high as 2,700 meters above sea level. It is able to last through an average temperature of 39°C (102.2°F), though it will die if temperatures drop below -5°C (23°F) for more than a short time. It flourishes best in climates with under 900mm of rain per year, though it can survive drought easily even though it prefers moist climates. All soil types except for acidic seem amenable to it, with some specimens even growing in cracks in rock faces.
Natural range
As its common name suggests, this plant is native to India, though it is actually found over a far wider range. It is unclear precisely where it originated, but it grows on a large number of islands and larger landmasses from central China all the way to eastern Australia. Its range includes the entire Indomalayan and Australasian regions.
Subtropical climates are most amenable to it, although it is found on both sides of the equator throughout its range as well as near the equator itself. Within this area it lives mainly in moist forests, particularly in coastal regions with mild weather; it likes large amounts of sun exposure, although it can survive partial shade. Many of the woodlands in which it lives are located at seasonal latitudes, and it is a common part of bamboo forests. In seasonal forests it loses its leaves and fruits with the seasons, while in equatorial forests it is evergreen and has non-seasonal fruiting.
Introduced
Because of its attractive appearance, West Indian lilac is often used as an ornamental plant in outdoor landscaping. As it can survive in many different soil types and in most tropical or subtropical biomes, it has been introduced to faraway parts of the world, such as the Americas. While it cannot survive in cold climates, it can live indoors or in botanical gardens; outdoors, it is known as far north as Virginia and as far inland as Oklahoma. Originally, it was introduced to North America in the warm Southeast, and has spread from there. In many places where it has been cultivated, but especially in the United States, it has spread into the wild and become invasive.
It was introduced to the Costa Rican island of Isla Nublar as a decorative plant by International Genetic Technologies during the construction of Jurassic Park in the 1980s and 1990s. In particular it is known to have been introduced to the primary Triceratops paddock, near a small stream and in an area of well-drained sandy soil. It was believed that the Triceratops did not eat the plant, but its berries were accidentally ingested periodically by at least one animal, since they were mixed in with stones used as gastroliths. When the island was abandoned in 1993, the lilacs were able to grow without human intervention; however their growth was probably restricted or eliminated between 2002 and 2015 when the island was reoccupied and built into the Jurassic World theme park. By that time it was well-known that they could be a health risk to the animals. As of 1993, the plants were fairly small but had already begun producing fruit, suggesting that they were around five years old and that their growth may have been stunted in some way.
Whatever their status as of 2015, they were probably eliminated entirely during the 2018 eruption of Mount Sibo, which destroyed most of the island’s forest and grassland habitats.
Ecology
Activity Patterns
During the day, the stomata of the leaves open to take in carbon dioxide. This is used as one of the components of the photosynthesis reaction. At night, the microscopic stomata close up.
Diet and Feeding Behavior
Like all plants, water is vital to the survival of West Indian lilac, but it can survive in drier soil and is tolerant of droughts once it reaches adulthood. It takes in carbon dioxide as well as water, using sunlight as a source of energy to recombine these compounds into carbohydrates. Oxygen is produced as a waste product. This species is known for being able to survive in very poor soil conditions, where nutrient availability is limited.
Social Behavior
Most plants are capable of limited interaction with one another using chemical signals. They may influence one another’s growth, warn of predators, and other actions. However, the specific ways that this particular plant influences its neighbors is poorly studied.
Reproduction
The Indian lilac produces both male and female flowers on the same plant, making it monoecious. The flowers are pollinated by insects and other animals; they are sometimes visited by various species of hummingbirds where they have been cultivated in Latin America, and by other animal species depending on where in the world they have been grown.
As with all flowering plants, it reproduces using seeds. Each seed is fairly small and musky-scented, with a tough casing containing meliatoxin and other neurotoxins. This discourages insects from feeding upon it, keeping the plant embryo within safe from predators. Similar toxins are found throughout the wood and other parts of the tree. Seeds are contained within fruit, a single fruit containing a single seed. Fruit is a unique reproductive strategy for plants as it has specifically evolved to be eaten by animals, and in the case of the Indian lilac, those animals are birds. Warm-blooded animals are all affected by its toxins in varying degrees, but it is not fatal to birds, merely causing a state of intoxication not unlike being drunk on alcohol. Birds may swallow the fruit whole or eat the flesh of the fruit away from the endocarp that surrounds the seed; in either case, the seed is exposed, and if swallowed along with the fruit it is usually transported a decent distance away. When the animal defecates, the seed is vented, and can germinate in a new environment. The seed must remain undamaged, of course, and has evolved to ensure this; if the endocarp is damaged, such as by being chewed or partially digested, the toxins are released.
The seed is only viable for a short time. It is best if it germinates right after being removed from a ripe fruit. After this, its life cycle is rapid for a tree this size; it reaches reproductive age by five or six years old, and typically only lives for about twenty years. Those that live in seasonal environments have yearly reproductive cycles, producing flowers in the spring or summer and bearing fruit that hangs all winter long. At equatorial latitudes, they produce flowers and fruit all year. Many thousands of fruits may be present on a mature tree all at once.
Communication
Plants use chemical signals, such as pheromones, to communicate with one another. They also use chemical signals transmitted through their roots, and most trees in forest ecosystems communicate and exchange resources through networks of subterranean fungi. The West Indian lilac may utilize these methods, but little research has gone into it.
Ecological Interactions
In their native range, West Indian lilacs are often a component of seasonal woodland and bamboo groves, and provide homes and food to many arboreal creatures. Birds are the most welcome visitors, since they are responsible for dispersing its seeds. The tree has evolved specifically for this, bearing fruits that are just the right size for birds to eat, and with toxins that are not fatal to them. Often, birds will gorge themselves on these fruits in excess. Birds (and other archosaurs) experience a state similar to drunkenness, showing imbalance and disorientation; in non-avian dinosaurs, symptoms also include labored breathing and microvesicles on the tongue, likely because the tree’s biology evolved long after these animals had become extinct. Because of this, the West Indian lilac tree is a known health hazard to herbivorous dinosaurs such as Triceratops, which may accidentally ingest the berries while foraging for gastroliths (smooth stones used to aid digestion). However, the toxins in the seed are not fatal to dinosaurs, just as they cause no permanent harm to modern birds. Some fruit-eating bats are also capable of safely dispersing the seeds.
In other types of animals, however, the plant’s poison is far more dangerous. Mammals are particularly susceptible to Melia toxicity, with humans and cats being well-known cases. While all parts of the plant are harmful when consumed by mammals, the seed is the most toxic part, so ingestion of the fruit is dangerous and often fatal when eaten in larger quantities. The cause of poisoning is damage to the endocarp of the seed. This is where the meliatoxins are stored in greatest concentration, and when the seed is damaged by being chewed on or digested, these toxins are released into the body and begin to cause harm. Symptoms include physical weakness, loss of coordination, loss of appetite, stomach pain, vomiting, constipation and/or diarrhea, lung congestion, internal bleeding, and cardiac arrest. Onset of symptoms may be about an hour after consumption, and death will occur about a day after symptoms begin.
The reason for this harsh evolutionary defense is actually fairly understandable when one examines its chemical composition. Meliatoxins are similar to the primary insecticidal component of neem oil, which is produced from a close relative of the West Indian lilac. This tree and its relatives are resistant to insect pests which would otherwise bore into its wood and consume its soft tissues; it repels them using its internal poison. Its flowers, too, are protected from predators by being too toxic to eat. If a predator survives the ordeal of eating an Indian lilac flower, it will likely never repeat its mistake.
As a widely introduced species, it interacts with a range of animals that are not native to its original habitat. For example, it is opportunistically pollinated by a variety of hummingbirds in Latin America, including the sapphire-spangled emerald (Amazilia lactea), glittering-bellied emerald (Chlorostilbon lucidus), and planalto hermit (Phaethornis pretrei). While it is now exposed to new pests, it is resilient against many of them; for example, in the Northern Hemisphere, the honey fungus (Armillaria mellea) is a pest on many trees, but the West Indian lilac is seldom affected by it or other fungi.
Cultural Significance
Symbolism
In North America, this plant species was considered emblematic of exotic foreign lands, with many of its English common names referencing countries it is native to (chinaberry, Indian lilac, etc.) and evoking imagery of faraway places. Because of this, it was imported to the United States as an ornamental plant around 1830 and has since become a long-lasting staple of the landscaping industry. However, its toxicity and potential as an invasive species cause some people to oppose its continued propagation. In this way, it has become a symbol of the perpetual conflict between conservationists and suburbanite landscapers, and for the shortsightedness of treating plants as mere decorations when they are actually living things capable of defending themselves. Melia azedarach was cultivated for its beauty, but has now spread throughout new environments to inadvertently poison household pets, mammalian wildlife, children, and anyone foolish enough to eat a fruit they have not conclusively identified. Despite these dangers, it is still commonly sold, and the conflict over exotic ornamental species continues.
In Captivity
This plant has been cultivated in its native range throughout history, and has in more recent times spread throughout the world in the flora trade. It was originally grown for lumber, though it has a wide range of other uses, and is valued as an ornamental plant outside its home ecosystem. Streets in the southeastern United States are sometimes lined with West Indian lilacs, although their abundant fruit falls may make for slippery sidewalks if not enough birds are able to safely access the plants and feed on the fruit. There are two major drawbacks to growing it in captivity: one, its seeds can survive in a wide range of soils and thus it may sprout where unwanted and become a noxious weed, and two, as few as six fruits can cause fatal narcotic poisoning.
To raise this plant in captivity, one must first ensure that the conditions are proper for it to thrive. Fortunately for the aspiring arborist of poisonous trees, it is a fairly hardy species, and can acclimate to various conditions. It will compete against other plants when rainfall is less than 900mm per year, though it can survive on as little as 600mm per year and once it grows larger it is quite drought-tolerant. Many soil types are amenable to it; while it prefers well-drained soils, especially sandy types, it can grow in most anything other than acidic soil. Sunlight is preferable, but it can tolerate partial shade. Warm conditions are ideal, but while it cannot survive prolonged cold or frost, brief exposure to chilly temperatures are survivable. To cultivate from the seed, botanists recommend cutting a small nick into the endocarp (or seedcoat); the protective casing helps to keep the seed inside safe from being eaten, but also slows down its ability to absorb water, so this helps to increase survival rates and speed up the growth process. Around 85% of seeds will survive the first two months, and can be potted once large enough to handle. Root cutting is also an effective method of propagation.
The tree will mature quickly, and can produce fruit at five or six years of age. At this point, controlling the spread of seeds is an issue of contention; if the plant is kept outdoors, it may be impossible, since wild animals will eat the fruit and bring the seeds to new locations. West Indian lilac trees will live for about twenty years: this is a short lifespan for a tree, but its reproductive rate means that its lineage will long outlive the person who planted it.
Science
Much research has gone into the toxins of Melia azedarach, which have been historically used for pest control. Scientists and gardeners alike have discovered that the substances extracted from this plant may be used to repel or kill insects, mites, nematodes, and even some fungi. At least two distinct meliatoxins and the triterpenoid chemical toosendanin have been extracted by scientists. Some of the toxins remain unidentified, such as those found in the tree’s resin, but research is still ongoing into what other substances it contains and not all are toxic; in 2009 and 2016, separate research projects discovered flavonoids (polyphenolic secondary metabolites, which may have health benefits) and phenolic acid (a chemical used in plastic synthesis and drug production) in the Indian lilac. As research continues, new potential applications of the substances produced by this chemical-rich plant are likely to be discovered.
A surprising discovery was made in 1993 by paleobotanist Dr. Ellie Sattler regarding this plant. International Genetic Technologies imported it as an ornamental plant to facilities on Isla Nublar, despite this species (and many of the other decorative plants) being toxic. Chief veterinarian Dr. Gerry Harding had noted a periodic health issue occurring in one of the de-extinct animals, a Triceratops horridus, though he dismissed lilac poisoning as a possible cause because the animals were not known to eat the plant. However, Dr. Sattler discovered that the animal was accidentally consuming berries that had become overripe and fallen off; in tropical climates such as Isla Nublar, the West Indian lilac often fruits year-round rather than seasonally, so this issue would not have been restricted to the plant’s standard reproductive cycle. Fallen fruit would land in the well-drained soil that this species favors, mixing in with rocks that the animals would use as gastroliths. Modern-day birds can consume the fruit without risk of dying, since the toxins only put them in a drunken state, but animals like the Triceratops originally lived and became extinct millions of years before the evolution of Melia azedarach. Therefore, neither the animal nor the plant are evolved to coexist. However, the biological traits that make birds capable of withstanding the poison appear to have already been present in non-avian dinosaurs; this can be determined by the fact that the Triceratops did not die, although its symptoms were more severe than those seen in birds.
Politics
Conflict over this plant’s propagation in nonnative regions is similar to that of all invasive ornamentals: on one side are the scientists and conservationists, who argue that this plant can displace native species and therefore disrupt ecosystems in which it finds itself, having far-reaching and unpredictable effects. There is also the argument to be made that its fruit is a public health hazard. In its native environment, people know how to handle this plant safely, but in places where it is introduced it is not as familiar, so children may sometimes eat the fruit and inadvertently ingest the poisonous seeds. As few as six can have fatal effects. The plant is also poisonous to cats and other domestic animals. On the other side of the argument are suburban landscapers who value the tree’s attractive appearance, considering any risks to be a tolerable consequence which people must adapt to as a cost of having this plant in their neighborhood. From a more practical standpoint, West Indian lilac also has a number of actual uses, such as for its timber and insecticidal byproducts.
For the time being, cultivation of Melia azedarach is not widely restricted. Despite its health hazards and the fact that it can quickly become an invasive weed, it is still easily commercially available from many plant nurseries.
Resources
Although the fruit is poisonous to humans and most mammals, Melia azedarach has plenty of uses. Its main resource is timber, and this is the primary reason it is grown in captivity. Wood from the Indian lilac is easy to work, a good balance between hard and brittle, and takes well to polish; is is lustrous and has a straight grain. The heartwood is reddish in color, easily distinguished from the yellowish hue of the sapwood. Red dye and rope can be manufactured from the bark, and the wood has a musky scent. Indian lilac wood can be used for virtually any project that requires wood, from building construction and furniture to tool handles and interior decoration. No matter the use, this species is favored because its wood is high in quality (often compared to its relative mahogany, but not in any danger of extinction) and resistant to pests such as termites and fungi.
Pest control is another major use of this tree. It produces a very large number of chemicals, not all of which are yet identified, but many of which are useful. The most obvious are insecticides. Its toxins are similar to azadirachtin, and they serve a similar purpose: they are harmful to insects and therefore discourage infestation. Pulp of the fruit is used to repel insects, and the fruit in powdered form is used to deter fleas. The leaves contain compounds which repel mosquitoes, mites, and nematodes; they and the fruits are often packed in with other plant products, typically other types of fruit, to keep pest insects from infesting them during shipping. Root bark has historically been harvested to treat parasitic infections such as ringworm; reportedly, fresh and dried bark can both be effective.
Other medicinal uses for the tree’s chemical products abound. It is a major feature in Chinese traditional medicine and remains in practice today for all manner of ailments. The leaves are used in diluted infusions for uterine relaxation, and extracts from the leaves are used to treat gastrointestinal parasites, diarrhea, kidney stones, digestive discomfort, tooth and gum disease, neuralgia, and headaches. Externally, they can be used to treat skin irritation. The bark of the stem is used as a bitter tonic in India, while the seed has antirheumatic properties (though it can only be used externally). In most cases, the pharmacological uses of the plant are essentially reduced versions of the toxic effects; for example, some of the toxins cause constipation, and so diluted concoctions can utilize it to treat diarrhea. However, using too much of any of these products is dangerous; it is not recommended to self-medicate using M. azedarach, and its products should be used only in moderation and preferably under the close supervision of a qualified pharmacologist.
The tree’s gum is said to have aphrodisiac properties, but this is probably untrue. Still, the gum is used to make a cooling drink, and is harvested from the base of the tree during the summer. The gum itself, often mistaken for sap, has no flavor. Other parts of the plant are consumed despite being toxic, and must be carefully prepared. The leaves are probably the most commonly used part of the tree; when cooked, they have a bitter taste and are used to flavor curry or soup. Not only humans eat the leaves, as Kenyan farmers have discovered that cattle can abide the taste and actually produce more milk on this diet. Finally, some humans do actually eat the fruit, despite the extreme risk of doing so. It is said to have a sweet taste. The flesh of the fruit is less poisonous than the seed, though not enough people are willing to risk their lives in order to gain any measurable data on the level of danger here.
Other uses for the West Indian lilac include the use of its seeds to make beads, for example in rosaries, and the harvesting of oil from its seeds. This oil is used for lighting and varnishing. Oil has also been extracted from the fruit itself, and can be burned for illumination. Its wood can be burned as fuel; this is efficient due to the tree’s fast growth and high reproductive rate. The calorific value of Melia azedarach is 5,100 kcal/kg. The live tree itself has use beyond what can be harvested from it, too. It plays a significant role in reforestation of threatened woodlands in its native habitat. This is especially common in Thailand, where local conservation efforts have found its rapid growth and tolerance for poor soil conditions make it an ideal species to commence the regrowth of deforested land. As it quickly reaches its full size, it creates shade that discourages the growth of weeds, and attracts birds and bats. Within a few decades, destroyed forests may start to show recovery when this tree is used. Thai conservationists have used this method to rescue woodland across the northern part of the country with a good degree of success. Humans also enjoy the live tree for the shade it provides. Outside its native habitat, it is prized as an ornamental plant, but this runs the risk of introducing an invasive species; it is probably best left to grow in its original environment, where it benefits the ecosystem that it has evolved to be a part of.
Safety
A common decorative species, Melia azedarach is found in many places where people live even far away from its native range in Southeast Asia and Australia. It is not especially dangerous when simply touched, but every part of the plant contains various toxins that make it harmful to consume. About an hour after the toxins from the seed enter the body (released when the seedcoat is damaged, either from chewing or digestive processes), symptoms will begin, probably starting with milder signs such as weariness and nausea before graduating up to more extreme effects. Cardiac arrest and other such symptoms often lead to death within twenty-four hours of consumption. If you begin to feel unwell in any way after consuming part of the West Indian lilac, especially the seed, seek immediate medical attention. Even if you feel fine, you should probably prepare for medical help if you realize you have eaten this plant.
It is fairly easy to avoid dying from Melia toxicity by simply not eating the plant, but still, deaths have been reported. The most common reason is simply not knowing how dangerous it is. Children may eat the fruits mistaking them for harmless berries, and even some adults believe that the fruit is harmless so long as the seed is not damaged. They may try to remove the seed from the fruit, eating only the fleshy parts. If this plant grows in your local area, it is important that you recognize it and understand that eating as few as six fruits can kill an average-sized child in less than a day. The fruits are not very big, so it would be easy to consume many of them before symptoms set in.
Outside of the plant’s natural habitat in Asia and Oceania, it can become an invasive species due to its hardiness and quick reproductive rate. Many overly-enthusiastic florists have introduced it around the world, and it is especially common in the southeastern United States where it has been cultivated since the 1830s. We cannot endorse the deliberate growth of invasive organisms, but this one is especially problematic because of how poisonous it is. Many people purchase ornamental plants for landscaping to give their yards an exotic look to impress the neighbors, but your neighbors will be significantly less impressed when new West Indian lilacs start to spring up in their own yards, shade out their gardens, and force their way up through cracks in their driveway. It is all too tempting to assume that, as a species native to the subtropics, it will not spread, and will in fact remain confined to your own yard. This is far from the case. Melia azedarach is a pioneer species, able to survive in soil of fairly low quality, and competes well against other plants. Additionally, while you may be aware of how toxic its fruits are, your neighbors’ children and pets may not be so well-versed in botany. It is quite likely that there are some attractive-looking plants you could grow that are actually indigenous to the place where you live, so perhaps consider cultivating these instead, to everyone’s benefit.
Behind the Scenes
The scene involving West Indian lilac in the film version of Jurassic Park is a loose adaptation of a similar scene in the novel, but the plant species used to represent it in the film is not actually Melia azedarach. For many years, Jurassic-Pedia staff assumed that Universal Studios had utilized Tetrazygia bicolor, which is also called West Indian lilac, either due to misunderstanding or for safety reasons (the latter is not a toxic species). However, the plant seen in the film does not closely resemble either M. azedarach or T. bicolor, and its exact identity is not yet known. In the film, Dr. Sattler diagnoses the Triceratops with symptoms of Melia toxicity, so for the sake of this encyclopedia, we assume that the plant featured in Jurassic Park was intended to be Melia azedarach as in the novel despite being portrayed by a different plant on-screen. Notably, the on-screen plant is smaller and much stringier than a West Indian lilac, although it can be seen bearing fruits (which also look nothing like West Indian lilac fruits).
