138 Bower .—On the limits of the use 
of morphological problems, and it will be noted that the 
anatomical method breaks down most conspicuously at the 
very points where questions of the nature of members arise, 
that is, where there is some marked peculiarity of external 
conformation. But it is not necessary on this account to 
throw anatomical evidence entirely on one side ; it may be 
taken advantage of as collateral evidence to support a view 
based on other and firmer ground ; still, since it is plain that the 
internal structure follows in great measure the modifications of 
external form and function, observations in this direction can 
never acquire first-rate morphological importance 1 . 
IV. Passing now from the consideration of the mature 
member, upon the characters of which it is found impossible 
to base a consistent distinction of members of different 
categories, to their origin and development, we may consider 
how observations on these points have been, or are used as a 
basis of classification of members. It was Schleiden who first 
laid special stress on development as the basis of morphology 2 ; 
and though his proposed distinction of axis and leaf according 
to the duration of apical growth is not now found sufficient, 
his service to the science in turning attention to development 
should not be underrated. His definition is as follows 3 : — c So 
ist also das Blatt die aus der Grundlage der Pflanze, der im 
Wachsthum und daher morphologisch unbeschrankten Axe, 
hervorgehende, im Wachsthum und daher morphologisch 
beschrankte Form ; unter diesen Begriff fallen alle Blatt- 
organe, und alle Axen sind ausgeschlossen.’ Though this 
distinction holds for the large majority of cases, still since 
stems of limited growth are known to exist (e.g. Welwitschia , 
species of Strep to carpus, the receptacle of Compositae, various 
1 Hofmeister, All. Morph., p. 415, states broadly, c TJebereinstimmungen oder 
Differenzen der ausseren Form, des inneren Baues, der Function sind nicht Maass- 
gebend fiir die Deutung eines gegebenen Gebildes als Achse, Blatt, oder Haar.’ 
He does not, however, give examples from vascular plants, which would bear out 
this statement as regards the internal structure. 
3 Grundziige der Wiss. Botanik, p. 20: ‘Die Grundlage fur alle specielle 
botanische Morphologie ist die Entwickelungsgeschichte.’ 
3 Grundziige, p. 172. 
