4i8 
I. W. BAILEY 
relatively large (figs. 47, 53). In gymnosperms and less highly differentiated 
dicotyledons, adjacent fusiform initials vary greatly in length and volume. 
The questions suggest themselves, accordingly: are the ray initials uninu- 
cleate and the elongated cells multinucleate, and are the striking variations 
in the length and volume of the fusiform initials closely correlated with 
fluctuations in the number of nuclei that are contained within them? 
Schacht (1856) and Russow (1882) were of the opinion that the elongated 
cells of the cambium contain more than one nucleus each, but Strasburger 
(1891) questioned the accuracy of their conclusions. 
During the last few years, I have secured material of the cambium 
from a wide series of gymnosperms and angiosperms of both temperate and 
tropical regions. The specimens were removed from various parts of the 
stems, roots, and branches and from trees of different sizes and ages, and, 
in the case of certain species, were collected at frequent intervals throughout 
the growing and resting seasons. The tissues were transferred as rapidly 
as possible to various killing fluids, of which the chrom-acetic-urea solution 
proved to be the most effective. In none of this material have I found 
cambial initials which contained more than one nucleus each. As shown 
in figures 47 and 53, the elongated initials, in tangential, longitudinal 
sections of the cambium, frequently appear to be multinucleate, but this 
is due to the fact that several radially flattened cells (fig. 50) are exactly 
superimposed so that their nuclei lie close to the same focal plane. It is 
evident, accordingly, that the fusiform cells of the lateral meristem do not 
resemble other types of large or much elongated protoplasts, such as have 
been shown, by Schmitz (1879), Treub (1880), Johow (1880), Kallen (1882), 
Haberlandt (1887), Pirotta and Buscalioni (1898), Smolak (1904), Nemec 
(1910), Lundegardh (1914), and others, to be multinucleate. Each initial 
contains a single nucleus which is centrally located and retains this position 
during growth and karyokinesis. In other words, not only is there a much 
greater variability in the size of the meristematic cells than hypothesized 
by Sachs or Strasburger, but in the lateral meristem the nucleus may extend 
its "energizing" influence to a distance of several thousand microns. Stras- 
burger found that the average diameters of the more or less isodiametric 
cells of terminal rneristems varied between 5 and 24 micrqus. In certain 
gymnosperms, the cambial initials may attain a length of more than 9,000 
microns and a volume of approximately 10,000,000 cubic microns. 
NUCLEO-CYTOPLASMIC RELATION 
Strasburger's measurements led him to believe that there is a close 
correlation between cell size and nuclear size, a conclusion which was 
strongly supported by the experimental investigations of Gerassimow (1902), 
and which has led to considerable controversy among zoologists and botan- 
ists as to whether the so-called nucleo-cytoplasmic relation is a constant 
and self-regulating ratio. The painstaking investigations of a number of 
