Asplenium majoricum is a tiny fern endemic to Mallorca (Serra de Tramuntana) and some locations in Valencia and south of Catalonia. It belongs to the family Aspleniaceae. This allotetraploid hybrid (2n = 144 chromosomes) is the result of crossbreeding between the diploid ferns Asplenium fontanum subsp. fontanum (2n = 72 chromosomes) and Asplenium petrarchae subsp. bivalens (2n = 72 chromosomes), followed by the spontaneous doubling of the number of chromosomes. Its fronds measure between 6 and 12 cm (5 in). The sori are longer than they are wide, with a side indusie, and are located near the central line of the pinnae. Sporulation occurs from March to November.