Orchids form an extensive family – more than 25,000 species have been described
Every year, Kew Gardens – the botanic gardens in London, in the United Kingdom – holds an orchid festival with a specific theme.
In the 2024 edition, the event organizers decided to honor Madagascar. Artists used more than 5,000 orchids and other organic materials to create sculptures, arches and arrangements illustrating the fauna and flora of this African island.
Along with other media, BBC News Brazil was able to access the greenhouse where the pieces were assembled before the exhibition opened to the public.
On this occasion, the scientists responsible for the care and study of these plants also shared the most curious scientific facts about orchids.
For example, one of these flowers served as an inspiration (and affliction) for the famous English naturalist Charles Darwin.
There is another species from this same family that provides one of the most appreciated spices in gastronomy: vanilla.
Orchids can also be key indicators of the health and balance of a given environment.
Check out the details about these and other strange scientific facts about these plants in this report.
A scene at the Kew Gardens Orchid Festival. In the middle, the artists assembled a baobab tree from the bark of other trees
Wide and diverse range
Along with daisies, orchids are part of one of the largest scientifically known families of plants.
According to estimates from Kew Gardens, more than 25,000 different species of orchids have been described.
They grow on all continents, except Antarctica.
Its versatility also attracts attention. The smallest orchids in the world, such as Platystele jungermannioidesIt is only 3 mm long.
the biggest (Vanilla planifolia) It has branches up to 20 meters long.
Tiger orchid, or Grammatophyllum speciosumIt has a flower up to 2 meters long.
Brazilian agronomist Marcelo Selaro, who works at Kew Gardens' herbarium, explained that although about 70% of orchid species grow on trees, they are not considered parasites.
This is because they only use the trunks and branches as support and do not extract any sap from the tree. For this reason, they are described as epiphytes.
Another curious fact about orchids mentioned by Selaro concerns the relationship between these plants and the animals that pollinate them.
About 60% of species in this family “trick” small insects, which are attracted to the flowers – even though the animals do not find any kind of reward there, such as nectar.
However, when interacting with an orchid, tiny animals emerge from the petals carrying pollen, which spreads throughout the environment and allows these plants to reproduce.
The tiger lizard reaches two meters in length
Inspiration for Darwin
A noteworthy chapter in the relationship between humans and orchids involves Darwin, the creator of the theory of evolution.
In 1862 he obtained a sample of Angraecum sesquipedalea species from Madagascar popularly known as the “star orchid” or “Darwin’s flower” – for reasons you will understand below.
This white and yellow flower has a striking feature: at the bottom, it has a very elongated tube, as you can see in the photo below.
The star orchid has a long tube at the bottom of the flower, which helped Darwin understand the evolution of different species
When analyzing the species, Darwin speculated that there must be an insect in the plant's habitat that had a proboscis (a type of tongue) so long that it reached the end of the tube and sucked the nectar that accumulated there.
This in turn ensures the spread of pollen from Angraecum sesquipedale.
But there was a problem: at the time Darwin made this assumption, no animals with these characteristics had been observed in Madagascar.
Some experts even ridiculed the English naturalist's hypothesis.
However, at the beginning of the 20th century, speculation about the “long-tongued insect” became reality: explorers identified the hawk moth, which actually possessed the characteristics described by Darwin.
It has been given the scientific name Xanthopane morganii praedicta – which in Latin means something like “anticipated butterfly”, a reference to Darwin's writings.
article Posted on the site From the New York Botanical Garden, in the USA, he recalls that the founder of the theory of evolution was an avid researcher of orchids and even wrote specific books about them.
And the Angraecum sesquipedale It ended up being a perfect example of coevolution, which occurs when two species — in this case, an orchid and a moth — interfere with each other's growth and adaptive abilities.
More than half of the orchids are classified as epiphytes and use the trees only as support
Rare spices
Another strange scientific fact related to orchids is the fact that vanilla is extracted from a plant belonging to this family.
a Vanilla planifolia It has an elongated shape and grows like a vine.
It is a typical species in Mexico, Central America and the northern part of South America, more specifically Colombia.
Vanilla is extracted from the pods that grow when the plant flowers. This fruit is dried and processed – Scores of Kew Gardens The Aztecs were the first to use it as a spice, in preparations that also included cocoa.
Nowadays, changes in habitat have made Vanilla planifolia an endangered species – and much of its cultivation for consumption is concentrated in places where humans introduced this orchid, such as regions of Africa and Asia.
Also according to Q, vanilla is the second most expensive spice in the world, after saffron.
The high value is due to the work required to grow this species. To get an idea, outside of its native habitat this plant needs to be pollinated by hand.
Vanilla – one of the most expensive spices in the world – is extracted from a plant in the orchid family
“The canary in the mine”
In an interview with BBC News Brazil, vegetable horticulturist Solene Dekoert describes orchids as “canaries in the mine” of environmental conservation.
This term refers to the practice of miners in the 19th century, who used to take canaries into coal mines.
The animal was used as a warning signal – if it died, there was strong evidence of toxic gases or lack of oxygen in that environment, and the workers would run out of the mine, before meeting the same fate as the poor little bird.
Orchids are very sensitive to environmental degradation
Returning to orchids, Decorette highlights that they are very delicate – and also indicate imminent danger.
“They are the first species to disappear [quando um ambiente começa a ser degradado]“, sums up the expert supervising the Prince of Wales Conservatory in Kew Gardens, where the Orchid Festival is organised.
“In other words, they are a good indicator of the health of the environment in which they live.”
Kew Gardens estimates that about 50% of the world's orchid species are at risk of extinction due to habitat destruction and climate change.
