There aren't many rarer British mosses than
Weissia multicapsularis, as it has fewer than 5 known colonies in the World! Its first Welsh record came from Dingestow in 1981 (when I was too young to appreciate mosses) and it was a thorn in my side, with 15 failed attempts at relocation, until I found my own colony about 1km from the original site in 2008. I revisited the colony this afternoon and tall, brownish, short-leaved
Weissia are frequent over the same area as I marked in 2008, although I completely failed to find any sporophytes to confirm the ID. The site seems utterly mundane - a steep bank in improved pasture - but also supports
Acaulon muticum,
Weissia squarrosa and lots of a small
Fissidens that looks likely to be
F. crispus. I suspect it has never been overly fertilised because it is too steep, and a combination of a SW-aspect, grazing and slumping prevent takeover by vascular plants.
Anyway, one patch of
Weissia had a little orange fungus growing at its base. I figured that a fungus growing on
Weissia multicapsularis could be pretty rare, so I carefully collected the fungus and 3 stems of the moss for identification. It looked rather ill-defined compared with most
Octospora that I have seen, perhaps because of the membranaceous margin (something mentioned on the excellent Bryoparasitic Pezizales site
http://www.octospora.de/Ltuberculatella.htm). Under the microscope it had remarkably lobed asci containing 8 strongly warted spores. A check on the Pezizales website suggested the only fungus recorded so far from
Weissia species is
Lamprospora tuberculatella, which has spores that are identical to my specimen. From what I can see on-line, there are no previous British records, so a very rare moss may support an even rarer (in British terms) fungus.
