of the terms ‘ Phyllome 5 and ‘ Caulome. ’ 141 
well-known definition of stem and leaf is as follows 1 : c Stem 
(Caulome) is merely that which bears leaves; Leaf (Phyllome) 
is only that which is produced on an axial structure in the 
manner described in paragraphs 1-7 :’ and he proceeds to 
say ‘that which is common to all leaves is their relation 
to the stem.’ How then about the possible so-called 
‘terminal leaf? can such a thing exist? On this point 
Goebel has written a remarkable passage which runs as 
follows 2 : ‘Terminal leaves are unknown in the vegetative 
region, though this is but a statement of experience, which 
would be put aside by the first well-grounded exception ; 
and doubtless a foliage-leaf would remain a foliage-leaf, even 
if it arose in a terminal position on the growing- point, but 
therewith the last developmental distinction between stem 
and leaf would disappear.’ This implies that some other 
basis of distinction would remain, by which the leaf might 
still be recognised as leaf when terminal, and not merely 
as a development of the axis, which it would be according 
to Sachs’ definition. What then is that distinction? The 
distinction, which Goebel would here recognise as overriding 
Sachs’ definition, is one based on comparison of nearly allied 
forms (a phylogenetic distinction), or possibly of successive 
members of the same individual. If then the possibility 
of a ‘terminal leaf’ be admitted 3 , the definition of Sachs 
appears to be an arbitrary one, and is not to be accepted as 
final. However, no actually ‘ terminal leaf,’ in the sense above 
indicated, has been observed. What we require at present 
is a suitable nomenclature for what is actually seen in nature, 
and that based upon the definition of Sachs is the best 
hitherto proposed. 
1 Textbook, ist English edition, p. 136. 
2 Vergleichende Entwickelungsgeschichte, p. 184. 
3 Compare Warming, 1 . c., p. xviii. Also Eichler, Bliithendiagramme, p. 48. 
This question would appear to have lost much of its interest and importance to 
those who accept Goebel’s view of the sporangium as a member ‘ sui generis.’ 
Beneath it, however, as indicated in the passage from Goebel above quoted, there 
lies a morphological principle, which is certain to acquire greater importance in 
the future. 
