Thank you for your answers. Excuse me for my ignorance Marc, but would you be so kind to explain to me why do you conclude that the soil is calcium-free? Has the low calcium soil content a protective role in moss growth?
Leucobryum is a moss of desaturated oligotrophous soils and a calcifuge. Thus, in order to have a control on identification, I asked if the soil is calcium free.
Leucobryum juniperoideum is indeed another possibility. Not every one agrees that it is a distinct species.
Thanks, Marc, for your answer. I don't know the concentration of calcium in this soil, and I doubt whether anybody knows it, at least if not measured in situ. It is basically volcanic soil, at the lakeside of Furnas lake, and it is not supposed to be calcium poor, but how this calcium behaves in micro-environmental conditions is an open question.