524 
J. G. GROSSENBACHER 
A paper by Klinken^ has just appeared, in which the subject of 
ghding growth is discussed from various angles. The study was 
based on serial and other radial sections of Taxus taken through the 
cambial region, and including both xylem and phloem. Longitudinal 
gliding growth was found to occur in the xylem but not in the phloem. 
The cambium cells were found to undergo unlimited gliding growth 
or independent elongation. They were found to undergo transverse 
divisions after attaining certain lengths. Some of his published figures 
also indicate that some of the xylem cells coming into contact with 
medullary rays are often bent and curve somewhat to one side. 
Neeff^ recently contributed some interesting observations on gliding 
growth. He noticed that in the wood the ends of some cells were often 
compressed between others where resistance to elongation appears to 
have been too great. A figure is given showing a case where two cells 
are being forced apart by an intruder; the two halves of a pit are forced 
apart. See figure 6, which is copied from Neeff. Similar occurrences 
were also found in the phloem, as shown in the same figure noted above. 
He also found cases in which pits, corresponding to those that had been 
displaced by gliding growth, had apparently been formed in the walls 
of new neighbors. On the other hand, instances were also noted in 
which the pit connections existing between cells prevented gliding 
growth or retarded it to such an extent as to cause a decided compres- 
sion or puckering of the growing cells. 
The fact that the bars of Sanio occurring in the most closely related 
cells of a radial row always form a continuous and unbroken bar is 
regarded as indicative that gliding growth is of very minor importance 
or is wholly lacking. According to Raatz^ the running of bars through 
only one or a few cells is indicative that the meristematic cell in 
which such bars originated underwent only a limited number of divi- 
sions before being forced out of the cambial zone by the progressive 
differentiation of the cells in the cambium sheath. The long bars 
that extend through one or more season's growth, on the other hand, 
are said to have arisen in a meristematic cell in the most active part 
^ Klinken, J. Uber das gleitende Wachstum der Initialen im Kambium der 
Koniferen und den Markstrahlverlauf in ihrer sekundaren Rinde. Bibliotheca 
Botanica 19: Heft 84, pp. 41, 1914. 
^ Neeff, F. Uber Zellumlagerung. Ein Beitrag zur experimentellen Anatomie. 
Zeitschr. Bot. 6: 465-547. 1914. 
^ Raatz, Wilh. Die Stabbildungen im secundaren Holzkorper der Baume und 
die Initialentheorie. Jahrb. Wiss. Bet. 23: 567-636. 1892. 
