Although its precise
age is contested, Britain’s oldest tree, the Fortingall Yew in Perthshire,
Scotland, is thought to be between 3,000 and 5,000 years old. It’s already
famous, but could be about to become even more famous. To protect it, it is
surrounded by a small stone enclosure with iron railings. That’s because
souvenir hunters were taking parts of the tree, and therefore damaging it (The Telegraph, November 1, 2015).
But Dr. Max Coleman of
the Royal Botanic Garden in Edinburgh, Scotland, noticed that a branch was
growing berries. This was unusual because the tree was male, and only female
yews grow berries. Was Britan’s oldest tree undergoing a sex change? Is it male or female?
The Fortingall Yew was
regarded as a male tree because it produced pollen, unlike female yews. Female
yews produce distinctive seed-bearing red berries. The Fortingall Yew had never
had red berries – not in 3,000 years or more. In October this year Dr. Coleman
found three red berries growing on a branch. He thinks the tree, or part of it,
might be changing from male to female. The rest of the tree still looked to be
male, and just one branch appeared to be female.
He said yews are
normally either male or female, and in autum and winter sexing yews is easy.
Males have small spherical structures that release clouds of pollen when they
mature. Females have bright red berries from autumn to winter.
Coleman said other
conifers, and even yews, have switched sex, so it was possible. The Fortingall
Yew seems to have just one small branch in the outer part of the crown that has
switched, and now behaves like a female.
Coleman has collected
the three seeds for further study to conserve the genetic diversity of yew
trees by planting them in the Botanic Garden.
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