76 HOW TO KNOW THE FERNS 



length of the frond, and sometimes less than 

 this. In most cases the stipes is of a purple 

 colour, and the leafy portion of the frond is of an 

 exceptionally fine green shade. The leaves are 

 freely produced in tufts and are roughly lanceo- 

 late in outline. The fronds of the Sea Spleen- 

 wort are only once pinnate, the pinnae which 

 are usually about an inch in length being, as 



Asplenium marimim. The Sea Spleenwort. 



a rule, oblong in outline, They are, however, de- 

 cidedly variable in form, some being egg-shaped. 

 A curious feature of the pinnae is that they are 

 unequal in shape at the base, the lower part 

 appearing to have been cut off whilst the upper 

 portion is greatly enlarged. Between the lower 

 pinnae the rachis is winged, but this feature 

 disappears at the tip of the frond where the 

 pinnae run together. 



The sori are to be found on the underside of 

 the pinnae, arranged in lines on either side of the 



