OSMUNDA

fern genus of the family Osmundaceae, with divided fronds and often growing to a height of 1.5 metres (5 feet). The matted fibrous roots of these abundant ferns are called osmunda fibre, osmundine, or orchid peat; they are broken up and used as a rooting medium for epiphytic orchids; i.e., those that derive moisture and nutrients from the air. For information on the Osmunda species, see Osmundaceae.