(from filum "a thread," quasi filatum incifa), 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 frondes." They constitute the first order in the class cryptogamia; and consist of Filices, which are divided into fructificationes, spica- tes, frondosae, & radicales. This order comprehends the entire xvith clas of Tournefort, in whose system the filices make only a single genus, in the first section of the above mentioned clas.

is also an order of plants in the fragmenta methodi naturalis of Linnaeus. See Botany, p. 469, col. 2.