Nature on our doorsteps: Bunches of keys
By Rosaleen Dwyer
Rosaleen Dwyer is the County Heritage Officer at South Dublin County Council – every week she gives us an insight into the natural heritage around us and the beautiful biodiversity of the plants and creatures
While the occasional shrivelled berry might still be spotted in hedgerows, almost all of autumn’s fruit, nuts, and seeds have long since disappeared.
These were either scattered by the wind or were devoured over the winter by hungry birds.
Ash's hard seeds are enclosed in long papery wing-case
Unusually though, Ash trees tend to hold onto its seeds over winter.
Instead, they shed these seeds in late winter or early spring, attracting animals like mice and squirrels who gather them to eat.
Some seeds are dropped along the way, just in time to sprout new Ash trees in springtime.
The seeds of the Ash are commonly called ‘keys’, because they hang from the tree’s branches like big bunches of keys.
They are also sometimes called spinners or helicopters, but the name ‘helicopter’ is more usually given to the seeds of the Sycamore.
From a distance, bunches of Ash keys look like withered leaves
From a distance, bunches of Ash keys look more like withered leaves, but a closer look shows them to be long, brown wing-cases that enclose the seed at one end.
The papery wing-case is paddle-shaped and slightly twisted, making it a perfectly designed aerodynamic feature.
As the seed falls, this shape causes the seed to spin sideways, away from the parent tree. This design inspired the development of helicopter rotor blades which are also tilted to change flight direction.
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