188 



CLASS CRYPTOGAMIA. 



.^ 



At Fig. 158, a is a fern, of the genus ^'&- ^^^ 



Asplenium, which bears its fruit on the 

 back of the fronds ; at J is a moss of the- 

 genus Hj23num, showing two of its flow- 

 ers borne on slender pedicels. At c is a 

 genus of the Lichen family. At d is the 

 Agaricus, one of the most common of the 

 mushrooms. It has been said, that Lin- 

 naeus, having arranged all plants which 

 would admit of classification, cast the re- 

 mainder into a heap together, which he 

 called Cryptogamous ; he did not, how- 

 ever, rest satisfied in thus throwing them 

 together, but subdivided this miscellaneous collection into or- 

 ders ; or we might more properly say that he gave names to 

 those divisions already marked out by nature. 



285. Order Filices^ or Ferns. — ^The First Order contains the 

 Ferns ; their plume-like leaves are called fronds. The fructi- 

 fication consists of one-celled spore-cases (called thecoe or sjyo- 

 rangia) which open in various ways and discharge the nimierous 

 minute sj^ores. Tlie fruit (sporangia), mostly disposed in dots 

 or lines, grows on the back, summit, or near the base of the 

 frond. Fig. 159, a^ rejDresents the genus polypodium, with 



sporangia in roundish spots on the back of the frond ; 5, as- 

 plenium, in lines nearly parallel, diverging from the center of 

 the frond ; c, blechnum, sporangia in uninterrupted lines run- 

 ning parallel to the midrib of the frond on both sides ; c?, pteris, 

 or brake, sporangia forming lines on the edge of the leaf. Some 

 ferns bear their fruit in a peculiar appendage, as a spike or pro- 



Orders marked out by nature.— 285. Ferns— JModea of the fructification of ferns. 



