Review. 
63 
CELAKOVSKY ON THE CORTICATION OF THE 
STEM BY FOLIAR BASES. 1 
H OFMEISTER first shewed that in the majority of leafy 
plants the outer cortex of the stem was formed by the 
decurrent bases of the leaves. Celakovsky further elaborates this 
by shewing firstly that in all cases where at the apex of the stem 
the leaf-rudiments are in complete contact with each other any 
two superposed leaf-rudiments arc separated, as seen in longitu¬ 
dinal section, by a perfectly acute angle, the apex of which is on 
the axis. As, therefore, a mathematical line divides the insertion 
of both leaf-bases, no free portion of the axis can possibly exist in 
that region. It follows that the internode formed at a later stage 
between the two leaves thus in complete contact with one another 
can only arise by means of an extension of the base of the upper 
leaf taking place simultaneously with that of the axis on which it 
is inserted. 
But cases occur in which the leaf-rudiments are, from the 
earliest stage, separated from each other by conspicuous areas of 
the central axis. These spaces constitute the “ Entwickelungsfelde” 
of the Schwendener-theory, the arena of the development of the 
young leaf which is gradually wholly occupied by the latter as it 
grows, both in breadth and thickness, more quickly than the axis 
itself, expands in the tangential and the radial directions respec¬ 
tively. This primary more rapid growth in thickness of the leaf- 
rudiment, which enables it to occupy the axial space intervening 
between itself and the leaf-rudiment immediately below, must not be 
confused (as was done by Hofmeister) with the subsequent extension 
of its base on formation of the internode. Further, this latter 
process involves a restitution to the axis of that which was originally 
taken from it. For the cortical tissue of the internode, although 
in its origin arising from the leaf (“ Blattbiirtig ”) must be regarded 
as pertaining to the stem (“ Stammeigen.”) This reciprocity in 
growth between the leaf and The subjoined stem-segment 
(“ Stengelglied ”) is an indication of the morphological unity of the 
two, and of the fact that they together constitute what our author 
terms the (“ Sprossglied.”) 2 
Celakovsky then proceeds to describe typical examples taken 
1 “Die Berindung des Stengels durch die Blattbascn,,” Flora, 
Heft, III., 19^2. 
1 .See his “Die Gliederug der Knulonie ” (Bot. Zeit. 1901),or my 
review of the same (New Phytologist, vol. I., January, 1902). 
