PTERIDOPHTTA. 



223 



and open by a pore or simple fissure of the tissues. The 

 leayes, which are very large in some species, are rolled (cir- 



FlG. 131. FlO. 132. 



Fig. 131.— Moonwort (BotryeMum lunaria), one of the Adder-tongues, 

 sf, the sliort stem bearing the divided leaf, fcs, of which b is the sterile, and 

 / the fertile, part. 



Fro. 132.— A common Fern (Polypodlum vulgare), showing the under- 

 ground root-bearing stem, and the leaves, one with round spore-dots on 

 its lower surface. Natural size. 



cinate) in the bud. The most important genera are An- 

 giopteris and Marattia. Some are cultiyated in fern-houses. 



