The dataset contains a key to species and locations of moss samples and water samples collected along with relative water contents for moss samples. The stable carbon (13C/12C) and oxygen (18O/17O) composition of cellulose is presented, along with the stable oxygen (18O/17O) and hydrogen (2H/1H) isotope compositions of fresh water and water samples distilled from moss tissue. Full details about this dataset can be found at https://doi.org/10.5285/1e57032c-327a-49c7-bb2e-43921dc116e2
