4 MORPHOLOGY 
tiply indefinitely by division. Finally these amoeboid cells begin to 
coalesce and a plasmodium is gradually built up (fig. 3). The in- 
dividual amoeba-like cells that enter into the structure of the plas- 
modium may lose their identity or not, but 
their nuclei do not fuse. A plasmodium, there- 
fore, is a mass of coalesced naked cells, each 
represented in the complex body at least by its 
nucleus. It would be confusing to indicate 
FIG. 3. A small group t h e variations that may occur in this life 
of amoeboid cells, each ... T , . ,,- . 
containing a distinct nu- hlstoI T- Tt ls sufficient to say that the flagel- 
cleus, beginning to coal- lum stage is regularly absent in certain forms, 
esce in the formation of anf i t h a t the flagellum stage and amoeba stage 
a plasmodium. Adapted . . . . 
from SACHS ma y enc y st repeatedly before the formation of 
a plasmodium. 
In general it may be said that the structure and behavior of the nutri- 
tive body of these organisms would seem to relate them to animals; 
but that the spore-forming structures are just as distinctly those of 
plants. 
2. SCHIZOPHYTES 
The name of the group means "fission plants," referring to the fact 
that the characteristic cell divisions occur in rapid succession and repre- 
sent the only method of reproduction. The two divisions of schizo- 
phytes are distinguished in general by the presence and absence of 
chlorophyll, which means that one group comprises independent, food- 
manufacturing plants, and that the other comprises parasites and 
saprophytes (see p. 61). 
(i) CYANOPHYCEAE 
General description. These are the blue-green algae, as indicated 
by the name, and very commonly they are presented as one of the groups 
of algae. This association is made chiefly because of the presence of 
chlorophyll, but the differences from the true algae are so important 
that the ability to manufacture food should not outweigh them. A con- 
sistent name for the group is Schizophyceae (fission algae), but we have 
retained the name which is in far more common use, and which refers 
to the most conspicuous feature of the group, namely, the usual presence 
of a blue pigment (phycocyanin) in addition to the green. This associa- 
tion of chlorophyll (?) and phycocyanin gives to the plants, at least in 
