Friday, 13 July 2018

Interesting Thamnobryum on Ramsey Island

During a boat trip round the island as a birthday treat for Sandra yesterday, we were taken into a small sea cave at the north of the island called Ogof Penclawdd, which had some dripping cliffs supporting a substantial growth of bryophytes. The cave must be drippy all year round I suspect given the prolonged drought we've had? Martin, the skipper surprisingly, but very kindly agreed to take up my request to see if there was any chance of grabbing a sample and with our guide Nia at the bow, they expertly procured a small sample to satisfy my curiosity.
Even without a lens to hand I could see it wasn't what I was very optimistically hoping it might be, Cyclodictyon laetevirens. Nevertheless it didn't look that familiar either, the complanate leaf arrangement being reminiscent of Platyhypnidium riparioides, so it was packaged in some cheese pasty wrapping generously donated by a group of teenagers.
Today under the miscroscope, the leaves were clearly Thamnobryum-like and being so complanate, maderense was foremost in my mind. Th. maderense is said to have 4-ranked rather than 8-ranked leaves, but the character isn't always that well defined according to some of the scant information I;ve managed to find online. Certainly some leaves look four-ranked and the plants bear little resemblance to the tree-like plants of typical alopecurum, the shoots being short and closely appressed to the substrate, so any comments/thoughts welcome as always.
A final word of thanks to Martin and Nia of Thousand Islands Expeditions for a great trip and for humouring me. Riding 'The Bitches' in Ramsey Sound was my highlight; even in calm conditions it was quite an experience, so I can't imagine what it must be like with a big tide and in a big sea?


  1. That looks really intriguing, Barry, and very different to typical Th. alopecurum. I think that I mentioned a complanate Thamnobryum in my Pembs Flora, but of course the only confirmed Welsh record of Th. maderense was our colony in Cwm Clydach. Differentiating these species is extremely difficult and is not necessarily always clear-cut. Perhaps Nick Hodgetts would be able to look at your specimen.

    I still hope that Cyclodictyon might be in a Pembs seacave somewhere...

  2. Unfortunately Nick said it is just odd looking alopecurum. It was good fun all the same!