age Spa a a ah ea Re i 
1900] THE CELL PLATE IN HIGHER PLANTS 79 
that the plasma membrane around each ascospore was formed 
by the growth and lateral fusion of the polar radiations, a proc- 
ess which is essentially similar to the formation of the cell plate 
in higher plants. 
In the division by which the ‘‘beaks”’ are cut off from the 
gametes in Basidiobolus, a typical cell plate is formed, accord- 
ing to Fairchild,’ from two rows of granules, whose origin was 
not discovered, in the equatorial region of the spindle. In some 
of the Sphacelariacee Swingle* confirmed the previous obser- 
vations of Strasburger, that the cell plate is not formed in a 
connecting spindle, but arises in the cytoplasmic network. 
Swingle suggested, however, that its formation may be under 
the control of the nuclei by means of the kinoplasmic fibers 
which radiate from the poles, although there are not enough of 
such fibers actually to form it. An important point in this con- 
nection is the fact that if the daughter nuclei are of unequal size 
the cell plate is formed nearer the smaller nucleus, as Debski 
described for Chara. In the oogonium of Fucus, Strasburger™ 
found a cell plate built of granules which he considers extra 
nuclear nucleoli arranged in the cytoplasm. The granules divide 
SO as to form two layers out of which are formed continuous 
membranes, Discussing the subject more generally, Strasburger” 
Places great emphasis upon the kinoplasmic nature of the cell 
plate. He points out the fact that the formation of a cell plate 
by the fusion of swellings of the connecting fibers is analogous 
to the formation of the plasma membrane around the ascospores 
as described by Harper. Inthe case of the ascospores there is no 
doubt of a transformation of the substance of the fibers (polar 
radiations) into a plasma membrané. In the case of the cell 
plate, while it is equally evident that there is a transformation of 
f ~ 6g Kerntheilung und Befruchtung bei Basidiobolus ranarum Eidam. Jahrb. 
: » Bot. 30: 285. 1897, 
ine dey Kenntniss der Kern- und Zelltheilung bei den Sphacelariaceen. Jahrb. f. 
* Bot. 30:297. 1897. 
* Kerntheilung und Befruchtung bei Fucus. Jahrb. f. wiss. Bot. 30: 351- 1897. 
cee, 1 
30: 375. vTBope oPlasmastructuren im Kern- u. Zelltheilung. Jahrb. f. wiss. Bot. 
. 
