I attended part of a day organised by Glamorgan Botany Group to look for Wilson’s Filmy- Fern Hymenophyllum wilsonii. This had been found by Tim Rich at Dare Valley Country Park among boulder scree at the base of a small corrie. He had found four plants and wanted to see if there was any more so about eight of us spent a couple of hours searching and clocked up over 50 records.
If there is one good way to learn about plants then searching for one species on your hands and knees is a pretty good way of getting your eye in. I don’t think I’ll forget what Wilson’s Filmy-Fern looks like in a hurry!
This is proving to be quite an interesting site because there is also a large colony of Fir Clubmoss Huperzia selago which along with the Filmy-Fern seems to have been overlooked by Victorian botanists from this area.
Any way I decided to go back and take some photos of the Filmy-Fern
I found what appeared to be 2 different types of leaves the plant on the left being flatter and paler, while the one on the right had more obviously curved leaves. Obviously I was thinking the one on the left could be Tunbridge Filmy Fern H. tunbrigense but closer examination with the microscope suggested this might be too much like wishful thinking.
Although the leaf veins do not quite reach the tips of the leaves the cells appear mainly rectangular so it is most likely to be Wilson’s Filmy-Fern. For comparison the following photo is the plant on the right, definitely Wilson’s.
I will go back later in the year to check the indusium margins which may be a more definitive character.