96 BOTANICAL GAZETTE [aucust 
After the cones have developed the nuclear wall breaks down, 
and the cones unite in two groups to form the bipolar spindle. 
3. As in Iris and Disporum, the spindle in Hesperaloe origi- 
nates froma weftof kinoplasm. The latter completely surrounds 
the nucleus and is of cytoplasmic origin. As in Iris, the fibrils 
of the weft run parallel to the nuclear membrane. 
By growing out at irregular intervals the weft develops a 
series of sharp-pointed projections which become the primary 
cones of the spindle. 
As the nuclear wall disappears, the cones collect in two groups 
and fusion at their apices brings about the bipolar condition. 
4. In Hedera, as division approaches, the cytoplasm close to 
the nucleus becomes changed into a weft of kinoplasmic fibrils, 
which orms a zone completely surrounding the nuclear mem- 
brane. 
This change in the form of the cytoplasm proceeds at 
intervals in such a way that the kinoplasmic zone appears to 
grow out in the form of projections. These projections terminate 
in sharp points and become the primary cones of the spindle. 
As the cones grow outward the fibrils composing them become 
more sharply defined, elongate, and converge at their apices. 
The events that follow are essentially the same as those in 
Iris, Disporum, and Hesperaloe, 
The method of spindle formation of the second division is 
a duplicate of the first. 
5. While the various methods of spindle formation described 
for the higher plants differ in certain respects, the resemblances 
between others are sufficiently great in warranting a classifica- 
tion of them. The following classification of the types is there- 
fore suggested : 
Type I, represented by Gladiolus, Iris, Disporum, Hesperaloe, 
Hedera, Osmunda. 
Type 2, represented by Cobaea, Passiflora, Lavatera. 
Type 3, represented by Equisetum. 
Type 4, represented by Agave. 
STANFORD oo 
Californ 
