FERNS 



1ST 



derive no nourishment from them ( 41). This habit be- 

 longs chiefly to the moist tropics, where plants may obtain 

 sufficient moisture from the air without sending roots into 

 the soil. 



108. Sporophytes. If an ordinary fern be examined, it 

 will be discovered that it has a horizontal underground 

 stem or rootstock ( 27), which 

 sends out roots into the soil, and 

 one or more large leaves into 

 the air (Fig. 179). These leaves, 

 appearing to come directly from 

 the soil, were once supposed to 

 be different from ordinary leaves 

 and were called fronds ; but al- 

 though the name is still used in 

 connection with fern leaves, it 

 is neither nec- 

 essary nor ac- 

 curate. These 

 leaves are usu- 

 ally compound, 

 branching eith- 

 er pinnately or 

 palmately. 



There are 

 two peculiari- 

 ties about fern leaves that should be noted. One is that 

 in expanding the leaves seem to unroll from the base, as 

 though they had been rolled from the apex downward, the 

 apex being in the center of the roll. When unrolling, this 

 gives the leaves a crozier-like tip (Fig. 179). The other 

 peculiarity is that the veins fork repeatedly (Fig. 180). 

 This combination of unrolling leaves and forking veins is 

 very characteristic of ferns. 



Probably the most important fact about the fern body 



FIG. 179. The habit of an ordinary fern (sporophyte), 

 showing the horizontal rootstock sending out roots and 

 leaves, and also the peculiar rolled tip of the developing 

 leaves. 



