470 Prof. Alexander Dickson on 



branch obliquely subtended, as usual, by the somewhat 

 bifid amphigastrioid scale " x" while if w^e look to the next 

 lateral leaf vertically below that adjacent to the branch, 

 w^e find that its auricle (PI. XV. fig. I,?) has undergone an 

 abnormal development, is amphigastrioid and bifid, and 

 altogether so closely resembles, in appearance and position, 

 the scale " x" that it is almost impjossible to resist the con- 

 clusion that the two are " serially homologous" : in which 

 case the scale " x" would fall to be considered as the auricle 

 of the adjacent lateral leaf "?/." 



It may be considered presumption on the part of one 

 who has not made these plants a very special subject of 

 investigation, to offer the foregoing criticism of the views 

 of the greatest authority in this department ; yet I cannot 

 but think that what I have observed is at least sufiicient 

 to warrant the demand for a very careful re-examination of 

 the intermediate steps between the initial stages and the 

 adult condition of the parts concerned ; since if there is 

 any fallacy underlying Leitgeb's views, it is probably due 

 to some error in the observation of these steps. 



Postscript. 



In justice to Mr Spencer, I must admit that the morpho- 

 logical confusion perpetrated by him might perhaps receive 

 some countenance in the more or less ambiguous utterances 

 which occasionally fall even from competent botanists. 



For example, Dr Masters {Tero.tology, p. 483), referring 

 to the conflicting views held wdth regard to the inferior 

 ovary and the so-called calyx-tube, says — " But this matter 

 loses much of its importance if the morphological identity 

 of axis and leaf-organ be conceded." Mr Spencer, indeed, 

 refers {Principles, ii. pp. 37-43) to statements by Dr 

 Masters as to the want of absolute distinction between leaf 

 and axis ; and it is possible that Dr Masters may, indirectly, 

 be responsible for Mr Spencer's remarkable speculation. 



Again, Professor Bower, in his able and valuable paper 

 on the Comparative Morphology of the Leaf in the Vascular 

 Cryptogams and Gymnosperms {Phil. Trans. Roy. Soc, 

 1884, part ii. p. 569), views " the whole leaf from apex to 

 base" '''as a podium or form of axis." And in the same 



I 



