Europe’s rarest fern has been discovered in Killarney, Ireland, leaving botanists baffled over how it remained undetected for so long.
The neotropical fern, Stenogrammitis myosuroides, has only ever previously been found in the mountainous cloud forests of Jamaica, Cuba and the Dominican Republic – more than 4,000 miles across the Atlantic.
Rory Hodd, an Ireland-based botanist who spotted the tiny plant in a remote upland valley far from the nearest road, said: “It’s rare to discover a new native plant species in Britain and Ireland – one that we think arrived ‘under its own steam’, not imported by humans – but it’s frankly amazing to discover a genus that’s completely new to Europe.”
It appears that the tiny fern has been overlooked for thousands of years while quietly enduring in the Killarney National Park in County Kerry – one of Europe’s last remaining fragments of temperate rainforest.
Hodd was plant-hunting when he discovered a few specimens of the fern growing on humid rocks. He collected and pressed one and dispatched it to Fred Rumsey, a senior curator at the Natural History Museum in London.
Working with American colleagues who are experts on these plants, Rumsey identified the tiny fern as part of a distinctive group known as the Grammitids, a rare variety that usually grows on trees in the tropics. Their findings have been published in British and Irish Botany, the journal of the Botanical Society of Britain and Ireland.
“The nearest occurrences we have for these Grammitid ferns is mid-Atlantic, in the Azores, where there are two exceedingly rare species which have recently been listed as critically endangered,” Rumsey said.
It is unlikely the tiny fern was brought to Ireland by people because Grammitid ferns have proved impossible to cultivate and this fern grows on rocks rather than other plants, so would not be accidentally introduced on tropical garden plants.
The scientists believe it is most likely that Stenogrammitis myosuroides is a relic from thousands of years ago when there was a very different climate, and quietly prospered on Europe’s mild Atlantic fringe.
Hodd said: “It also highlights the immense value of temperate oceanic rainforest, a habitat that is now mostly lost and highly degraded, as a refuge for a wide range of species that would not survive without its protection.”
The Kerry mousetail has been suggested as a common name for what is the rarest fern in Europe, although Hodd pointed out that the name did not quite capture one small fern’s apparently miraculous ability to confound expectations and leap across oceans.