Root

Fern roots are generally thin and wiry, although some are fleshy and either slender (in the Ophioglossaceae) or as much as 13 mm (0.5 inch) in diameter (e.g., Acrostichum and Marattia). The relation of the roots to the stems is a valuable identification tool. For example, in certain tree ferns (e.g., Cyathea and Cibotium) and in the royal ferns (Osmunda), the entire stem surface is covered by masses of roots. If large enough, the dead tangles of tree fern roots can be cut with a saw into various shapes suitable for attaching epiphytic greenhouse plants, and pieces of such root masses have proved to be useful in horticulture for cultivating orchids and bromeliads. Because of the massive destruction of tree ferns for this purpose, the importation of tree fern logs into many countries is now prohibited. Certain tropical ferns have elaborately hairy roots whose surfaces are covered with locks of silky golden or brown root hairs.