140 Narrow- Leaved Chain-Fern 



ate, next oblong or obovate with cuneate or truncate base, then 

 elliptical or oblong-ovate or oblong-lanceolate and early lobed 

 below. From PI. XXXVII can be seen how, in subsequent leaves, 

 the lobes enlarge, and more and more lobes are formed, from 

 the part of the blade above the first lobes, which enlarge also; 

 until the lobes become the primary segments and the part of the 

 blade left above them forms the apical section of the mature leaf. 

 These segments sometimes in turn become lobed. Their lobes 

 are rounded, and, so far as I have seen, are less deep than the 

 lobes of the primary segments in O. sensibilis. 



The margin of the blade, except at base, is more or less 

 crenulate at first. Later the crenulation becomes serrulation. 

 The number of teeth mostly corresponds with the number of 

 marginal veinlets: except near the rachis, each marginal veinlet 

 usually terminates within a tooth. 



The veins are free at first. The leaf's primary midvein, if 

 not evident at the beginning, becomes so before areolae appear. 

 One or two areolae form first in the upper part of the blade while 

 the blade is still simple. Others follow in subsequent leaves, 

 forming downward on each side of the primary midvein, and 

 thence outward until the margin of the blade has the appearance 

 of cutting the network of veins: the marginal veinlets are mostly 

 free. The primary midvein is finally more or less hidden in the 

 rachis of the mature leaf. 



The midveins of the leaf's primary segments (secondary 

 midveins) are formed in the same way as in O. sensibilis, and 

 start, as on that plant, from the ends of the paracostal areolae 

 next the blade's primary midvein. In the mature leaf they are 

 more or less concealed in the segments' midribs. The areolae 

 between them, as in O. sensibilis, have the appearance of being 



