Structure and Origin of “ Cladophora Balls." 
5 
ing to the needs of the plant, into “rhizoids,” “cirrhoids” or 
“ stolons.” Fig. 2, B, shews a branch of this nature which is giving 
off rhizoids from many of its cells. 
“ Stolons” are organs of propagation. They are in the nature 
of long runners which form vegetative shoots at their ends either 
directly as in Fig. 2, C, or indirectly by altering the shape of the 
end cell and putting out branches. 
The “ rhizoids” are not rhizoids in the true sense, i.e., 
colourless hair-like structures developing from the lower end of the 
plant. It is generally agreed that from its earliest stages the plant 
has no distinction into rhizoidal and cauloidal parts. It has, 
moreover, no polarity or rather it has a changeable polarity. This 
is well illustrated in Fig. 3, A, where the plant has changed its 
direction of growth through an angle of 90 n , i.e., from aa to bb. 
The vegetative branches are putting out rhizoids from their terminal 
cells and new vegetative shoots in an opposite direction. Changes 
in external condition can alter the polarity of the main axis and 
cause vegetative branches to develop from the older part of the 
plant in a backward direction as well as a forward one. 
Multiplication. According to Brand (loc. cit.) multiplication 
only takes place in the Aegagropilas in vegetative ways. The cells 
can perennate in unfavourable conditions. They are of exceedingly 
slow growth and of great age. The oldest cells of the axial column 
die off gradually in regular succession under normal conditions. 
The death of these cells sets free the lateral branches in regular 
acropetal succession. The plants have a limited size and the branches 
when set free, form the main axis of a new individual which branches 
and grows and in its turn forms new individuals by the death of the 
cells of its main axis. In this way the plants resemble the 
Sphagnaceae and can be said to possess an unlimited duration of 
life. 
Brand (loc. cit.) does not agree with Kjellman 1 that there are 
special resting cells or “ basal gonidia.” He states that in 
Kjellman’s plants there were an unusually large number of dead 
intercalary cells and that the cells remaining were only old stem 
cells which had survived adverse external conditions but which had 
no special significance as reproductive bodies. It is certainly true 
that, whether or not they have any special significance as reproduc¬ 
tive bodies, these isolated old axial cells have the power of rejuvenating 
1 F. R. Kjellman. “ Zur Ot'ganographie und Systematik der Aegagropilen.” 
Nova Acta Reg. Soc. Sc. Upsala, Ser. Ill, Vol. 17, 1898. 
