There are very few records of Loeskeobryum brevirostre in Glamorgan. The map below (drawn from the Mapmate datatbase) shows 3 dots in the Vale of Neath, although the top dot is actually on the Brecon side of the Afon Pyrddin. Two other occurrences which (for some reason) are not in the database, and therefore not on the map, are Clydach Vale, RCT (Sam Bosanquet) and Morlais Hill, Merthyr (Roy Perry and Alan Orange). Even then it's just 4 known sites in Glamorgan, which suggests to me that it may be under-recorded, particularly when compared to neighbouring counties.
Mapmate Distribution of Loeskeobryum brevirostre in Glamorgan
Loeskeobryum tends to be associated with the sorts of humid woodlands that are typical of the South Wales valleys, occurring with familiar species like Hylocomium splendens, Rhytidiadelphus loreus, Dicranum majus and Plagiothecium undulatum. Sam describes it as a moss which is irregularly encountered and of unpredictable occurrence in Pembrokeshire and Carmarthenshire and Roy Perry described it as rare in the Flora of Glamorgan, citing only the Morlais Hill records. The most recent records for Glamorgan (Briton Ferry Woods and Maesgwyn) are pretty disjunct and, interestingly, in Larch plantations. Larch plantations (there are still some left!) often support a luxuriant bryophyte ground flora and I have often thought of them as surrogate sessile oak woodlands in South Wales. Perhaps it is not surprising that Loeskeobryum has found a home in them.
It's easy to pass over Loeskeobryum when it occurs with other robust woodland mosses like Rhytidiadelphus spp. In habit it's somewhere between Eurhynchium striatum and R.loreus.
Loeskeobryum brevirostre, Briton Ferry Woods
However, once you've got it under the lens the pleated leaves with distinctive, long, narrow points are unmistakable.
Loeskeobryum brevirostre, Maesgwyn
Mature conifer plantations may not seem like the sort of place to look for species like Loeskeobryum brevirostre, but they are surprisingly good habitats for all sorts of bryophytes.
There must be more of this species in Glamorgan.