80 COMPOUND ORGANS OF PLANTS. 



FILICES, OR FERNS. 



109. The Ferns are the most highly developed of the Cryp- 

 togamia, or flowerless plants. The higher representatives of 

 the family possess roots, conspicuous stems and leaves, whilst 

 almost every kind of vascular tissue enters into their compo- 

 sition. 



110. We give the name of frond (^frons, a bough) to the 

 foliaceous appendages of the stem of ferns, because they 

 appear more analogous to branches enlarged into leaves (as 

 for example to the foliaceous and flattened branches of Phyl- 

 lanthus amongst flowering-plants), than to leaves, properly 

 speaking. 



111. The lower representatives of the family of ferns are 

 found in Europe and in all temperate climates, and are deve- 

 loped as perennial, herbaceous plants, from a rhizome or pros- 

 trate stem, which either creeps horizontally along the ground, 

 or burrows beneath its surface the fronds which it produces, 

 annually perishing, without producing an elevated trunk. 

 These herbaceous ferns seldom rise more than three or four 

 feet above the ground. They prefer moist, shady situations, 

 and are found overhanging the margin of streams and rivulets, 

 or springing from the crevices of rooks which they cover and 

 adorn with their bright green feathery fronds. 



112. A considerable degree of heat as well as humidity ap- 

 pears to be requisite to the complete development of ferns. 

 Beneath the warm bright sun of the tropics, they attain the 

 noblest arborescent forms. The united and persistent basis 

 of the decayed and fallen fronds forms an aerial stem, which 



