We’re getting used to celebrity public transgender announcements but did you know that plants can also change their sex? The Fortingall Yew (Taxus baccata), proclaimed as the UK’s oldest tree is undergoing a partial transformation from male to female.
Yew trees are dioecious (meaning ‘two houses’) so plants can be either male or female. Male plants produce pollen, and female plants have bright red berries. The Fortingall Yew in Perthshire, Scotland, believed to be anything from 3000 to 9000 years old has always been described in records as a male plant. But a few months ago local experts noticed that one small part of the upper canopy was starting to produce female berries.
It’s not an unknown phenomenon for trees to change sex – some conifers do it and ash trees are notorious for switching. The plant’s hormones are altered by environmental factors, or perhaps age. Botanists at the University of Tuscia in Viterbo, Italy have recorded instances of female yew trees changing to male, and noted that female yew trees are more prone to suffer stress.
Experts believe that the Fortingall Yew has been able to change sex in part of the canopy because of ‘compartmentalisation’. As tourists have taken parts of the tree over the years, (in the early 19th century large limbs were removed to make souvenirs) the tree has developed into distinctly separate trunks, so one part can change sex without affecting the rest of the tree.
Seeds from the female part have been collected and will used as part of a project to protect the genetic diversity of yews across the UK and Europe, as they are usually grown from cuttings to make uniform hedge plants. The Edinburgh Botanics will soon feature a hedge of seed-grown yew trees.
And according to Pink News, the yew’s partial transformation makes it an ‘intersex’ tree, not transgender.
Read more at the Royal Botanic Gardens Edinburgh blog