Filicales

(fil-e-kā'lecz,) or FILICES. (Bot.) An alliance of plants, cla Acrogens, commonly called FERNS, and consisting of arborescent or herbaceous perennial, very rarely annual plants; those of arborescent habit having atrunk varying from 2 or 3 to 60 or 80 ft. in height, and formed of the consolidated bases of the fronds, surrounding a soft central ma of ti ue; those of herbaceous habit either having a caudex formed on a plan similar to the arborescent kinds, but on a smaller scale, the young fronds forming the growing point, or having a more or le fleshy rhizome whose growing point is in advance of the development of the fronds, which are produced from its sides instead of its apex. Arborescent Ferns are represented in Fig. 323. All true ferns, under which name are included nearly all the ferns that are Fig. 323.- TREE-FERNS. (Java.) known, may be recognized by the circinate growth of their young leaves, and by their hypo phyllo us fructification. The fronds are very various in regard to size and form, some being simple, others many times cut or divided; while some measure but an inch, and others many feet, in length. In the majority of instances there is no material difference of aspect between those fronds which are fertile and those which are sterile; but in others, including whole groups, the Acrostic he a for example, there is a manifest contraction of the fertile fronds, which are sometimes reduced to mere ribs and spikes clustering with ma es of the spore-cases. Many schemes have been proposed for the cla ification of ferns, but that one seems to be preferable, which is based on the modifications of the vascular system taken in conjunction with the fructification. [s. 364]