COMPARATIVE DISCUSSION 481 



sterile frond, which however arises vnot laterally, but in a median position. 1 

 Of these various views, which all coincide in attempting to refer the 

 spike in origin to a leaf or part of a leaf of the ordinary vegetative 

 sequence, only that of Goebel may be considered to hold the ground at 

 the present time. 2 



The arguments advanced by Goebel in support of his theory were 

 primarily a comparison of malformations, especially in Botrychium Lu'naHa. 

 It was pointed out that here the normally sterile leaf shows most various 

 intermediate steps of fertility till, in extreme cases, it may be wholly 

 represented by a fertile sporophyll (Fig. 242, p. 443). It is recognised that 

 in these cases there has occurred a true metamorphosis of a foliage leaf into a 

 -characteristically formed sporophyll, which differs in a striking manner from a 

 foliage leaf. The inference which Goebel drew was "that this is also the 

 case in the normal and usual sporophyll, i.e. that this is produced from 

 a part of a foliage leaf." This argument has been dealt with at length 

 elsewhere. 3 But more recently Goebel has strengthened his position by 

 observations on the young leaf of Helminthostachys.^ He does not give 

 any account of the first origin of the spike, which in Botrychium has 

 been traced and found to be different from that of the sterile pinnae, 5 

 but lays stress upon its similarity of form to the sterile lobes, upon its 

 dorsiventral character, and upon the development of the lateral wings in 

 abnormal cases, like those of the foliage leaves. He concludes : " We can 

 therefore trace back the sporophyll to a specially far-reaching transformation 

 of the vegetative leaf." 



In his admirable discussion on teratology in Schenk's Handbuch* 

 >fessor Goebel has drawn attention to the fallacious conclusions 

 rhich may be arrived at, on the assumption that malformations 

 illy afford evidence of the morphological nature of the parts con- 

 irned ; he has quoted as an example the malformations of the ovule, of 

 lich specimens may be selected, so as to illustrate the gradual steps 

 abortion of the nucellus and integuments, together with correlative 

 relative growth of the funiculus, till the result is reached that the 

 rhole ovule is replaced by a simple leaflet ; 7 but he concludes that this 

 inal result shows how little justification there is in accepting the vegetative 



Schenk's Handbuch, vol. iii., p. ill; Organography, vol. ii., p. 481. 

 2 Sufficient reasons for setting aside Keeper's theory have been given in Studies, ii., 

 46. The position of those who speak of the spike as a " ventral lobe " of the leaf 

 irs somewhat obscure : if by this is meant a body which may exist in the vegetative 

 ite, then either it must have been marginal or ventral in origin : if the former, the 

 is that of Goebel : if the latter, then it lies with them to show that such vegetative 

 parts exist in these or other plants. But the term may connote a ventral part which has 

 been fertile throughout descent : in that case the view is coincident with my own 

 advanced in 1891 (Proc. A'.S., Dec. 17, p. 270), and now submitted again in a modified 

 form. 



* Studies, ii., p. 8. 4 Organography, vol. ii., p. 481-485. 



5 Bruchmann, !.<:,, p. 218. 6 Vol. iii., pp. 114-125. 7 Loc. cif., p. 121. 



2 H 



