1coo] THE CELL PLATE IN HIGHER PLANTS 85 
In order to show clearly certain zonal differentiations in the 
spindle as well as other general structures in the cells I have 
used photo-micrographs for many of the illustrations. I have 
considered this the more satisfactory, inasmuch as my prepara- 
tions have showed some phenomena varying markedly from the 
descriptions of other observers. 
OBSERVATIONS. 
For purposes of description we may group the phenomena 
under three heads representing three stages in the development 
of the cell plate, viz., preparatory ; genetic; growing. 
1. . Lhe preparatory stage. 
At the time when the chromosomes have collected at the 
equator to form the equatorial plate the spindle is of the form 
that Hof has recently termed ‘“ monaxial,” 7. ¢., a spindle having 
a single axis but not necessarily ending in single definite points 
as poles (figs. r, zo, 23). The poles of the spindle in both the 
larch and the onion are jn most cases somewhat blunt. In the 
latter plant my observations agree entirely in this respect with 
those of Hof (Z.c.) and Nemec (2. c.). In the case of the larch 
T have not confirmed Strasburger’s 3? observation of a centro- 
sphere. In my preparations the poles generally appear blunt as 
they do in the onion, 
The fibers which appear in connection with this stage may 
be grouped into three systems, connecting fibers, mantle fibers, 
and radiating fibers. These systems correspond in general to 
the system of fibers similarly named by older investigators, 
especially among the zoologists, except that here, as will appear 
later, the distinction cannot be so sharply drawn between con- 
necting fibers and radiating fibers. If we study the above 
mentioned Systems of fibers more in detail, it will appear that 
while Many of the connecting fibers are collected into thick | 
Strands or bundles, and others appear as single fibers, such an 
arrangement does not indicate a necessary difference of charac- 
eves frequently a single fiber diverges from a bundle and 
* Karyokinetische Probleme fig. 25. 
