BOTRYCHIUIM RUTACEUM. 32:} 



continental neighbours, —more familiar with the plant than 

 ourselves, having more materials than ourselves, and having 

 devoted more attention to the subject than ourselves, — arrive 

 at and maintain an opiuion which we are not fully prepared to 

 adopt. On making the comparison in question, and confining 

 it strictly to the barren branch, it does not seem to me that we 

 are justified in saying that one form is a modification of the 

 other ; that the linear piunate leaf at page 313, would, by a 

 greater or less amount of cutting or subdivision, or by a greater 

 or less amount of luxuriance, become, or even approach, the 

 deltoid but equally simple leaf at page 332. It happens that a 

 divided form of B. lunaria is not uncommon ; but in this, the 

 flabelliform pinnae are split to the base, becoming completely 

 digitate, and thus receding still more from the habit and cha- 

 racters of rutaceum. 



The varieties of this fern very much favour the idea of its 

 being specifically distinct from B. lunaria. If we regard dis- 

 crepancies in size as varieties, then are they most abundant : 

 if we regard discrepancies in the amount of division as varieties, 

 then also are they most abundant. I have felt great interest 

 in examining and comparing the barren branches of a series of 

 these ferns : sometimes they are so small as readily to escape 

 notice unless sought for, and appear as a green scale, less than 

 the eighth of an inch in length and breadth, and scarcely even 

 undulated at the margins : from this almost rudimentary state 

 we may trace them up to the fully developed and divided form 

 which I have figured on the opposite page ; and this, again, is 

 probably not by any means an unusually luxuriant or developed 

 specimen. Now, through all these gradations of size and 

 discrepancies of division, there is no approach to the cognate 

 species ; on the contrary, the characteristic outline is most 

 faithfully preserved. There is, moreover, in this species, in 

 common with its congener, a great tendency to malformation 

 or multiplication of parts ; thus, fronds with two or three fer- 

 tile branches are by no means uncommon, and, in some instan- 

 ces, as in the example figured by Mr. Cruickshank overleaf, 



