GLIDING GROWTH AND THE BARS OF SANIO 
Krabbe^ made a special study of the subject of gliding growth and 
found that it is typical of the cells differentiating to form the char- 
acteristic cellular elements of fibro vascular bundles in both mono- 
cotyledons and dicotyledons. He found that in the case of certain 
monocots practically the entire xylem of the secondary fibrovascular 
bundles arises from single vertical rows of cells which grow many 
times their original length gliding past each other, thus producing a 
bundle instead of a row of cells. He holds, however, that cell elonga- 
tion occurs only while the cells adjoining are still growing. The same 
was maintained by him regarding the special enlargement of certain 
cells to form vessels; i. e., gliding growth in the transverse direction. 
Mischke,^ as well as Nathansohn^ later published some inferential 
corroborative evidence supporting Krabbe's findings. A more recent 
substantial contribution to the subject of gliding growth is by Jost.^ 
In his study of the behavior of the cambium in crotches and where 
branches arise from a trunk, he has concluded that although con- 
tinued increase in thickness of the two components at such branching 
points necessitates a reduction in area of the cambial mantle or sheath, 
no cambium is actually eliminated. He therefore assumed that the 
cells of the cambium glide between each other as the area to be covered 
becomes smaller and that the cytoplasmic connections obtaining 
between the cambial cells are re-established at the conclusion of the 
gliding growth. He also thinks that primary rays of stems are divided 
and the parts displaced laterally to form many narrow rays by the 
gliding of the cambial cells in such a way as to break up the very 
broad primary rays. 
wicklung des Cambium, und N. J. C. Miiller's Ideen iiber diesen Gegenstand. 
Bot. Zeit. 33: 809-14; 825-29; 841-45. 1875. Russow, E. Uber die Perforation 
der Zellwand und den Zusammenhang der Protoplasmakorper benachbarter Zellen. 
Sitzungsber. Naturforscher. Gesellsch. Univ. Dorpat. 6: 562-82. 1884. Schenck, 
H. Ueber die Auskleidung der Intercellulargange. Ber. Deut. Bot. Gesellsch. 3: 
217-24. 1885. Sanio, K. Jahrb. Wiss. Bot. 9: 123; Bot. Zeit. 21: 107-108. 1863. 
Haberlandt, G. Die Entwicklungsgeschichte des mechanischen Gewebesystems, 
p. 44, 1879. 
2 Krabbe, G. Das gleitende Wachsthum bei der Gewebebildung der Gefass- 
pflanzen, pp. vii + 100, pi. 7, 1886, Berlin. 
^ Mischke, K. Beobachtungen iiber das Dickenwachstum der Coniferen. 
Bot. Centralbl. 44: 39-43; 65-71; 97-102; 137-42; 169-75. 1890. 
^ Nathansohn, A, Beitrage zur Kenntniss des Wachsthums der trachealen 
Elemente. Jahrb. Wiss. Bot. 32: 671-86. 1898. 
^ Jost, L. Ueber einige Eigenthiimlichkeiten des Cambiums der Baume. 
Bot. Zeit. 59: 1-24. 1901. 
