I 12 



it may be even at their bases, forming twin fronds, or other- 

 wise normal plants, to fronds which ramify to an indefinite 

 e.'^tent from the base upwards to form wide fans or even 

 mosslike balls. As a general rule, however, the cresting 

 is terminal and even, the subdivisions of the frond dis- 

 playing precisely the same character as the frond itself, only 

 on a smaller scale, so that the heavier and more pronounced 

 the crest is at the frond tip, the greater the probability that 

 •the cresting will extend to the minor divisions ; and the 

 cases are rare where these latter are markedly crested and 

 the frond tip scarceb/ so, and still more rare where the 

 frond is well tasselled and the side divisions not at all. 



A peculiar feature of the tasselled ferns is their unreduced 

 fertility as regards spores, the sori being almost invariably 

 extended into the cresting in robust plants. This fact is 

 the more remarkable, as generally w^here the leafy area of 

 a frond is abnormally extended, as in the plumose or extra 

 divided Ferns, this is correlated with a reduced spore 

 production or even with complete barrenness, as we may 

 see in the crispum or frilled Hartstongues and the several 

 forms of Polypodiiun camhviciim. This difference is, how- 

 ever, partly accounted for by the fact that in many crested 

 forms of Ferns the minor divisions are more or less 

 contracted as if to counterbalance the extra area involved 

 in the tassel at their tips. 



As a rule, the spores of crested Ferns reproduce the 

 cresting truly, but not infrequently their progeny varies so 

 that a batch of seedlings may consist of exact reproductions 

 of the parental type mixed with others which are of more 

 marked character or the reverse, and even without crests at 

 all ; these last, however, are never, in our experience, normal 

 unless the parent is normal, with only a somewhat variable 

 crest on merely forked lines, indicating inconstancy or lack 

 of fixity of type. The faculty of cresting is very often 

 associated with other abnormal characters, such as 

 congested or extra foliose or more finely-cut frondage, and 

 as the tassels themselves differ very widely in character, some 



