FERNS. 



71 



rudiment of a stem exists underground in what is 

 called a rhizome, from which 

 the fronds shoot out, in 

 the same manner as the 

 leaves spring from the buds 

 of other plants ; these fronds 

 have a strong midrib which 

 is commonly called a stalk. 

 There are said to be between 

 two and three thousand va- 

 rieties of Ferns ; some of 

 them, in the tropics, attain 

 the enormous height of 

 thirty feet. Their growth is 

 extremely interesting, the 

 fronds opening in a peculiar Ferns, 



manner, unwinding them- 

 selves, as it were, from a round ball. The seed- 

 vessels are placed on the back of the fronds in little 

 spots or bunches, and the seed is so fine as to be only 

 perceptible under the microscope. Ferns thrive best 

 in moist and warm situations ; if grown under a glass 

 vessel which will confine the moisture, they form a 

 beautiful and interesting parlor ornament. 



