Asplenium ceterach Rustyback C DD N
There were beautiful examples of this fern to be seen growing from cracks and in the grikes of the limestone pavement all over the Burren. The young whitish coloured spores on the backs of the young fronds (LHS) turn red when mature (RHS) giving Asplenium ceterach its English name of Rustyback.
This fern is common all over Ireland and in the south west half of England includng all of Wales. It does occur elsewhere in mainland Britain but in smaller numbers and hardly at all in central and northern Scotland.
The name changed in 2010 (New Flora of the British Isles Third Edition by Clive Stace) from Ceterach officinarum to Asplenium ceterach.