Skye Fern Project

Last year, local BSBI Recorder Stephen Bungard was approached by Royal Botanical Gardens Edinburgh (RBGE) with the offer of funding for a DToL plant-based project, designed to run throughout 2022. Stephen notified members of the Skye Botany Group and asked us to come up with a worthwhile project. Between us we came up with various ideas before eventually coming to a decision. 

Firstly we would undertake a survey of Skye's polypodies in an attempt to clarify the distributions of Polypodium vulgare, Polypodium interjectum and of their hybrid Polypodium x mantoniae. Accurate determination to species level depends upon microscopic examination of the sporangia and, in the case of the hybrid, of the spores themselves. With the funding received from RBGE, the Skye Botany Group purchased a decent compound microscope. We have produced a polypody cribsheet and an online recording form which allows recorders to upload details of the samples they have collected, after which they will pass on the samples to those of us with access to a compound microscope for full determination. At the moment this consists of Nick Hodgetts, Stephen Bungard and myself with Joanna Walmisley currently looking after the Skye Botany Group's new compound microscope.

The second part of our project involves finding new populations of the two adder's-tongue ferns that occur on Skye. Ophioglossum azoricum is fairly widespread on neighbouring Raasay and yet is only known from four sites on Skye. It must occur here more widely than that. We know the precise plant-communities it prefers, so will survey likely-looking clifftop grasslands for its presence. Ophioglossum vulgatum also occurs on Skye but has yet to be found north of Portree. Again, we will be specifically searching likely-looking grasslands in an attempt to locate more populations, particularly in the north. 

We shall be writing an Ophioglossum account for the Darwin Tree of Life Project and we have been asked to collect a sample for full genome sequencing, the publishing of which would be a fitting legacy to our project.

Small Adder's-tongue Ophioglossum azoricum on Raasay. Coming to Skye soon....

Below are the BSBI distribution maps for each of the three Polypodium taxa and for both of the Ophioglossum ferns as was known at the end of 2021. Green squares indicate that the record has been made after 2020, faded squares indicate pre-2000 records. 

The two red squares to the lower right have now been re-identified as P.vulgare

I'm very much hoping that by the end of our project there will be a greater spread of green squares for all five taxa. It would be particularly satisfying to add recent records of the hybrid polypody, the old records have never been refound/validated in recent years and the Balmacara records have now been shown to be Polypodium vulgare.

Intermediate Polypody Polypodium interjectum growing epiphytically on a mossy Elder