Nature Notes - The Mallorca Pages
Ferns and fern-allies
There are far fewer species of ferns and fern-allies in Mallorca than in Skye, owing to the much drier conditions. There is only one clubmoss species as against 6 in Skye, but the Mallorcan one is much easier to find than any of the Skye ones as it is common on damp shady walls. It is Toothed Clubmoss, Selaginella denticulata, shown on the left. Mallorca also has 3 horsetail species, but I didn't see any of them.
Only a couple of true ferns were at all common, Southern Polypody and Rustyback. The picture on the right is taken looking down into an underground cave. I took it because it was so unusual to get as many as 4 fern species in a single picture, though on Skye it would be easy. They are: Maidenhair Spleenwort in the top right corner, Rustyback to its left, Southern Polypody in the middle left and Black Spleenwort (sensu lato) lower down on the left. The plant in the middle right is probably Geranium Purpureum.
c 8.6 cm from base of first pinna to tip of frond
These two pictures show Southern Polypody, Polypodium cambricum (= P australe), which was one of the most abundant plants of any kind. It was the dominant plant on stone walls, which line many of the roads. It's remarkable that this fern species has adapted to thrive on dry walls exposed to the baking Mediterranean sun. The second most frequent fern was Rustyback, Ceterach officinarum, which often accompanied the Polypody on walls. I didn't take a picture of it as I have some from Skye. Other than these two species, you could botanise all day without seeing a fern.
In a wooded area of limestone rocks near Esporles, the fern above left was quite numerous, and I'm baffled by it. It looks just like the British fern Black Spleenwort (Asplenium adiantum-nigrum). This is not given for the Balearic islands in Flora Europaea or the Balearic Flora website, though Dr Beckett's book lists it as a possible Mallorcan species. On the other hand, the closely related Asplenium onopteris, which I was hoping to see, is said to be fairly common in Mallorca. It has the tips of the fronds and the pinnae pinched out into long tapering points. I was not able to convince myself that any of the plants I found were A onopteris, especially as it requires acid rock and all the ones I found were on limestone, which A adiantum-nigrum tolerates happily. There are plants far closer to A onopteris in shape right here in Portree than any I found in Mallorca, see for instance the second picture on the Skye Black Spleenwort page, although A onopteris is not supposed to occur in Britain. If anyone can tell me what the Mallorcan plants really are I would be pleased to hear from them.
A definite new tick for me, however, was Asplenium petrarchae (above right), only found a couple of times in dark rock or wall crevices where it was very difficult to photograph. The fronds are covered with glandular hairs. Maidenhair Spleenwort (Asplenium trichomanes ssp quadrivalens) was about as common as Black Spleenwort, and in similar places, plus occasionally found on walls. The subspecies is the same as the one found in Skye, so I didn't bother with photos.
Not to be confused with Maidenhair Spleenwort is the Maidenhair Fern itself (above left), in Britain native only in the far south-west, but not uncommon in Mallorca, though it requires a very wet habitat such as the splash zone of a waterfall or artificial fountain. Finally, a mystery fern growing on a wall. Have drawn a complete blank with this one, which I only saw once.
The only remaining fern to mention is Bracken, Pteridium aquilinum. I came upon a couple of small stands of it in rough ground close to the road. The bulky tufted Dryopteris and similar-looking species that dominate our own fern flora were nowhere to be seen. Mallorca does have one Dryopteris species, D pallida, but it is not common and I didn't see it.