Growing on a suburban house wall
No interactions present.
The very common subspecies which is often found in cracks in brick walls and other very lime-rich spots. Subspecies trichomanes is a lime-hater and not nearly so common. There is also a rather rare third subspecies - pachyrachis.
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can you give us a bit more 'ordinary' guidance. I thought I knew trichomanes well!
In the UK there are 3 subspecies. A. trichomanes subsp. quadrivalens is a calcicole (ie it likes lime). Naturally occurring on limestone and other basic rocks it has found a really good niche on mortared walls, cement cracks and similar and is the subspecies commonly seen. Told by the rather rectangular shape of the pinnae at least those in the centre of the frond, with the pinnule stalk joining the pinna at the bottom corner nearest the rachis (or main stem). The rachis is rather wiry and the fronds tend to be sinuous and mainly keep fairly parallel to the substrate.
Subspecies trichomanes is the opposite. A calcifuge, so it hates lime. The pinnae are rather triangular with the stalk in the middle of the base of the triangle. The fronds tend to stick out from the substrate. They often lose their pinnae during the winter but the rachis remains, with many of its pinnules missing.
Both start with a dark rachis but although this remains in subsp. quadrivalens it turns a rather fine coppery red later in the season in subsp. trichomanes.
That leaves the rather rare subsp. pachyrachis. It is rather smaller, and tends to spred very close to the substrate, almost flattening itself against it. The pinnae are very distinctly lobed, those nearer the base of the fronds often having auricles (ie a lobe parallel with the rachis) and unlike the other two the pinnae tend to overlap. It is said that the pinnae have a hyaline (ie transparent) margin, but this can sometimes be difficult to see.
Not sure whether that helps or make things more confused!
Thanks Chris - the whole community should thank you.
There's a lot of Maidenhair Spleenwort on the Site. I wonder whether.....
The specimen at http://www.ispot.org.uk/node/118460
Looks like a candidate for subsp. trichomanes. One should try to avoid immature specimens as they often haven't fully developed their character but it certainly looks possible.
Now I'm looking closer, I found a really luxurious version today in a gorge of pretty basic mixed igneous rock - no lime or mortar. Much longer fronds than I've even seen. I have some photo's but no time at the mo to uplaad - they'll come and I'll link to/from here..
Lat/Lng: 50.4708, -3.5069
OS grid ref: SX931645