COMPARATIVE DISCUSSION 481 
sterile frond, which however arises not laterally, but in a median position.} 
Of these various views, which all coincide in attempting to refer the 
spike in origin to a leaf or part éf a leaf of the ordinary vegetative 
sequence, only that of Goebel may be considered to hold the ground at 
the present time.? 
The arguments advanced by Goebel in support of his theory were 
primarily a comparison of malformations, especially in Botrychium Lunaria. 
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, “e. that this is produced from 
a part of a foliage leaf.” This argument has been dealt with at length 
elsewhere.? But more recently Goebel has strengthened his position by 
observations on the young leaf of Helminthostachys.t 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 
Professor Goebel has drawn attention to the fallacious conclusions 
which may be arrived at, on the assumption that malformations 
really afford evidence of the morphological nature of the parts con- 
cerned; he has quoted as an example the malformations of the ovule, of 
which specimens may be selected, so as to illustrate the gradual steps 
of abortion of the nucellus and integuments, together with correlative 
vegetative growth of the funiculus, till the result is reached that the 
whole ovule is replaced by a simple leaflet;’ but he concludes that this 
final result shows how little justification there is in accepting the vegetative 
4Schenk’s Handbuch, vol. iii., p. 1113 Organography, vol. ii., p. 481. 
? Sufficient reasons for setting aside Roeper’s theory have been given in Studies, ii., 
p- 46. The position of those who speak of the spike as a ‘‘ventral lobe” of. the leaf 
appears somewhat obscure: if by this is meant a body which may exist in the vegetative 
state, then either it must have been marginal or ventral in origin: if the former, the 
view 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. #.S., Dec. 17, p. 270), and now submitted again in a modified 
form. 
3 Studies, ii, p. 8. 4 Organography, vol. ii., p. 481-485. 
5 Bruchmann, /c., p. 218. ®Vol. iii, pp. 114-125. 7 Loc. cit., p. 121. 
2H 
