sphag·num 'sfag-nəm n
1) any of an order (Sphagnales, containing a single genus Sphagnum) of atypical mosses that grow only in wet acid areas where their remains become compacted with other plant debris to form peat
2) a mass of dehydrated sphagnum plants used as a surgical dressing esp. during World War I
Medical dictionary. 2011.