4 
Revieiv . 
REVIEW. 
Celakovsky on “ The Segmentation of the Stem.” 
RE we justified in saying that our doctrines of the general 
morphological construction of the axis of the higher plant 
are essentially correct ? According to Professor L. Celakovsky, of 
Prague, who writes in the Botanische Zeitung , Heft V./VI. of last year, 
under the title of “ Die Gliederung des Cauloms,” our writers of 
text-books and botanical authors generally are largely in the dark 
as to the real facts connected with the building-up of the stem. 
After referring in his introductory remarks to the orthodox 
views on the structure of the stem as found in the text-books of 
St. Hilaire and Schleiden, he opens his first chapter, entitled “ The 
Articulation of the Stem in General,” with a consideration of those 
axes possessing amplexicaul leaves ; such he terms holocyclic stems, 
and regards them as being constituted of a series of “ stem- 
joints ” (Stengelglieder) placed one above the other, each occupying 
the entire diameter of the axis and terminating at the node in a 
leaf. As each leaf arises from that portion of the apex which 
becomes the stem joint to which it belongs, we may legard, he 
says, the leaf along with the lattter as a morphological unity, and 
term it a Sprossglied (shoot-segment). The entire monocoty- 
ledonous embryo (apart from the root) represents a first such 
“Sprossglied,” the hypocotyl being its holocyclic “ Stengelglied.” 
Holocyclic articulation is characteristic of monocotyledons. 
The second type of stem-articulation is that called mericyclic , 
in which each of the stem-joints occupies a portion only of the whole 
diameter of the stem, as in the case of spirally-arranged leaves. In a 
stem with ■§■ phyllotaxy the three “ Sprossglieder ” are united in the 
centre of the axis as three wedge-shaped portions instead of each 
occupying the whole diameter as in a holocyclic stem. Mistaken 
ideas have always been entertained as to what constitutes the 
internodes in such stems : usually the internode has been held to be 
that portion of the stem intervening between any two leaves, but this’ 
according to the “ Sprossglied ” theory, is absurd, the true internode 
necessarily lying between two superposed leaves. In stems with whorled 
leaves the internodes consist of serial stem-joints grouped at the same 
