Nemalion multifidum , Ag, 3 2 5 
and finally cannot be distinguished, the cells becoming typical mature 
strand cells of the central core. 
At the tip of the thallus the central strands are very active, the 
terminal cells cutting off segments rapidly, from many of \vhich new apical 
cells arise as lateral outgrowths. Some of the branches thus formed become 
new central strands, but most of them develop into assimilative branches 
(Text-fig. i, b } c). So quickly does this development take place that the 
assimilative filaments completely surround and hide the central portion, and 
it is not unusual to find mature procarps within a distance of their own length 
of the tip. The nuclei of the apical strand cells are very large and present 
a strongly reticulate. appearance. In the cells of filaments destined to con- 
tinue as central strands no chromatophore can be found (Fig. 7), but these 
appear very quickly in the cells 
of developing assimilative fila- 
ments. 
While most of the assimi- 
lative tufts arise at the tip of 
the thallus, new tufts are con- 
stantly being interpolated be- 
tween old ones farther back. 
In the development of the 
tufts two methods of growth 
are present. First, growth 
may take place by apical cell 
division. This is the method 
by which all branches already 
formed increase in length. 
The apical cell lengthens until 
it is three or four times as 
long as broad. The nucleus usually divides before the chromatophore 
(Figs. 4-6), although in germinating carpospores the reverse is more often 
the case (Figs. 81, 90). Second, growth may be by budding. Buds may 
be of two kinds, those leading to the development of side-branches 
(Text-fig. 2, a ), and those which give rise to trichomes (Text- fig. 2, b), The 
latter always grow out from a terminal cell, the former from a subterminal 
one. The bud which is to develop into a side-branch is put out as a papilla 
at the upper end of the cell. The chromatophore moves to the opening 
into the papilla and there divides, one-half passing into the bud. The 
nucleus divides, and one daughter nucleus passes into the new cell, which 
is then cut off. The new branch, thus begun, develops by apical growth, 
and, as it matures, gradually takes on an appearance of equality with the 
main branch, giving rise to a condition of false dichotomy. True dichotomy 
is not present in Nemalion, 
Text-fig. i. The growing apex of the thallus. 
a. Apical cell of a young assimilative branch, b. Lateral 
budding to .form a new branch, c. Terminal cell of a 
central strand filament, x 700. 
