(from filum "a thread," quafi filatim incisa), Ferns; one of the seven tribes or families of the vegetable kingdom, according to Linnæus, by whom it is thus characterized: "having their fructification on the back side of the fronds." They constitute the first order in the class cryptogamia; and consist of 16 genera, which are divided into fructificationes spicatae, frondosae, & radicatae. This order comprehends the entire xviiith class of Tournefort, in whole system the filices make only a single genus, in the first section of the above-mentioned class.

Filices, is also an order of plants in the fragmenta methodi naturalis of Linnæus. See Botany, p. 1317.