65 



with the fact that the frond and its subdivisions develop 

 apically, that is, the cellular growth is engendered at the 

 extreme tip. 



If we examine the incipient bud of a tree we shall find it 

 to consist of a compact bundle of young leaves, which, 

 when the bud bursts, emerge and grow, so to speak, all 

 over, expanding in all directions, so that the outline alters 

 but little except as regards expansion. A fern frond at 

 the same stage is a small, fleshy knob, devoid of any indica- 

 tion of foliar structure ; it is, in fact, only a rudimentary 

 stalk, tipped with a mass of incipient cells. By means of 

 these cells the stalk lengthens, and an incurved top is 

 formed, within which a process of division and redivision 

 goes on to the extent determined by the form of the frond, 

 simple or decompound, until, if decompound, all the parts 

 of the frond in a small and delicate form may be found to 

 exist in the still curled -up terminal at the top of the now 

 long stalk. After this it grows all over, leaf fashion, and, 

 as it does so, the coil unrolls, the parts straighten them- 

 selves, and ere long we see the broad, flat frond full size 

 and mature. Obviously this mode of development is more 

 compatible with tasselling at the tips than that of the leaf, 

 since all that is necessary is that the rest of the formative 

 cell work in the coils being completed, the terminal cells 

 split up and finish off with more points than the normal one. 



All the same, however, we must rank this occurrence 

 with the many other natural marvels, when we consider 

 that in the more highly-developed crested or cristate forms 

 in which the smallest subdivisions are tasselled, as well as 

 the largest, this means that many hundreds, or even thou- 

 sands, of formative cells, which normally would, as it were, 

 fix the last brick on the pinnacle, unanimously take it into 

 their heads, so to speak, to pile up a few more on the top 

 as a sort of radiating finial. This eccentricity is the more 

 remarkable as no species shows it as a normal character, 

 though it must be assumed to occur sporadically on most 

 species, seeing that out of about 44 native species of ferns 



