FERNS. 49 



CHAPTER V. 



FERNS, OR FII/ICES. 



THE general appearance of plants belonging to the 

 class of Ferns is so well known that it need scarcely 

 be described, especially since the introduction of the 

 glass plant-cases, by means of which the air can be 

 kept so damp that ferns are now grown in the very 

 heart of our cities. Their bright green and finely 

 cleft leaves (PL II. figs. 9 & 16) or fronds (from, a 

 leaf) as the leaf- like organs of the lower plants are 

 called, arising in tufts from the stems, give them the 

 elegant appearance we are called upon to admire, 

 whenever they are met with. The brownish spots or 

 stripes seen upon the back or under surface of the 

 fronds, and consisting of the fructification, form also 

 a simple character by which they may generally be 

 distinguished ; although in a few of them the fructi- 

 fication is placed upon a distinct stalk. The stem or 

 rhi'zome (pl^aypa, a root) of a fern is mostly situated 

 just beneath or at the surface of the ground, and is 

 commonly mistaken for the real root, which is buried 

 in the earth. It is brownish outside, and covered 

 with scurfy scales or r amenta (ramentum, a shaving). 

 These scales are interesting microscopic objects, from 

 the distinctness with which they exhibit the cellular 

 network. 



A section of the rhizome exhibits the fibro-vascular 

 tissue arranged differently from that in the stems of 

 either Exogens or Endogens. It forms curiously 

 curved longitudinal plates, a very abundant compo- 

 nent of which is the scalar'iform (scala, a ladder) 

 duct (PI. II. fig. 34). The walls of the scalariform 

 ducts are angular, and the secondary deposit is ar- 



