In what is being described as a sign of global warming, an exotic plant in the United Kingdom has produced male and female cones outdoors. This is believed to be the first time this phenomenon took place in 60 million years.
Two plantsof cycads, a primitive tree that used to dominate the planet 280 million yearsago, have produced cones on the sheltered undercliffs of Ventnor Botanic Gardenon the Isle of Wight.
Native toJapan, the species is usually only found indoors as an ornamental plant inBritain. Nevertheless, one of the garden’s plants has produced what is believedto be the first outdoor female cone on record in the UK.
“For the first time in 60m years in the UK we’ve got a male cone and a female cone at the same time,” said Chris Kidd, the curator of Ventnor Botanic Gardens. “It is a strong indicator of climate change being shown, not from empirical evidence from the scientists but by plants”.
Cycads usedto live in what is now Britain millions of years ago in an era when the Earth’sclimate had naturally high levels of carbon dioxide. Fossils of the plants werefound in the Jurassic strata of rock stretching from the Isle of Wight to theDorset coast.
Seven years ago a plant growing outside at Ventor had produced a male cone. But now different plants have produced flower-like male and females cones, giving botanists the opportunity to transfer pollen and generate a fertilized seed.
Kidd arguedthat the recent summer’s heatwave and the record-breaking temperatures havecaused the plant’s production of cones, with a run of milder winters alsohelping. Records kept at the botanic garden show that the highest averagetemperatures for January 100 years ago were lower than today’s lowest averagefor the same month.
“It’s not something that’s happened with a short-term mild spell. It’s a longer-term warming which is making these things happen,” he said. “The plant will have made the decision to commit to cone production in summer 2018, and that production is set in place to run through over winter and produce the following year.”
Cycadspecies are composed of three families, the only surviving members of anancient and largely extinct lineage that has changed little since the Jurassicperiod, and so are considered “living fossils”. All cycads are native to warmerparts of the world, but are naturally absent from Europe and Antarctica.