In early August 2006 the small reddish moss above appeared just in front of the sallow log.
Eventually I got round to sending some to Howard Matcham,our Sussex bryophyte recorder, and he confirmed my suspicion that it was Bryum rubens. This species has small tubers on the roots, hence the English name.
I had hoped to get fruits to make identification easier, but there was some very heavy summer rain which apparently destroyed the whole colony as none has reappeared. Beaten to a pulp by rain drops and grit from the compost.