Some similarities to : Green Spleenwort but that has green stalks and mid-ribs (rachis), rather than blackish, and to
Rusty-back but that has alternate leaflets attached to the mid-rib along their widest part rather than at a single point as in Maidenhair Spleenwort.
Inhabits old walls and rock faces, concentrated mainly in the west of the UK, but is found in all places. Far more common that is Green Spleenwort, which, in the UK, occurs only in the west. The central park of the blackish stalk has scales.
No close relation to: Maidenhair Fern or
Maidenhair Tree [plants of a similar name].
There are three sub-species, two sharing the same common name, Maidenhair Spleenwort:
It is not known if any of the above photographs correspond with any of these; the two sub-species of Maidenhair Spleenwort are slightly less ubiquitous that the pure-bred, whereas
Lobed Maidenhair Spleenwort (Asplenium trichomanes subsp. pachyrachis) which has lobed leaflets. [RRR]
Maidenhair Spleenwort (Asplenium trichomanes subsp. quadrivalens) which has symmetrical oblong (rectangular-ish) leaflets.
Maidenhair Spleenwort (Asplenium trichomanes subsp. trichomanes) which has asymmetrical leaflets. [RR]
Lobed Maidenhair Spleenwort is only found in very few localities in the UK. All three are very similar and are often distinguished only with difficulty, the size of the spores being the only truely reliable way!
There are several hybrids and hybrids of sub-species:
Once again, it is un-known if any of these hybrids correspond with any of the above photographs.
Alternate-leaved Spleenwort [Asplenium × alternifolium] (A. trichomanes × septentrionale)
Asplenium × clermontiae (A. trichomanes × ruta-muraria)
Asplenium × confluens (A. scolopendrium × trichomanes)
Asplenium × lusaticum (A. trichomanes ssp. quadrivalens × trichomanes ssp. trichomanes)
Asplenium × staufferi (A. trichomanes ssp. quadrivalens × A. trichomanes ssp. trichoman)