58 
PACIFIC SCIENCE, VoL XIII, January 1959 
branch develops from the outer end of the 
basal cell of a lateral whorl member (Fig, 2b, 
c). The initial of the new branch divides trans- 
versely, forming a chain of 16-20 cells before 
cells in the central part of this chain divide 
laterally to cut off basal cells of the new whorl 
(Fig. 2c). These basal cells are arranged 
roughly in an anticlinal spiral, and divide 
rapidly to form the whorled laterals when 
the new branch emerges from within the 
old branch. 
All cells are uninucleate, with a large, dense 
nucleus usually in the mid-part of the cell near 
the periphery. The chromatophores vary 
greatly in form, but are constant in any one 
type of cell. In the outer cells of the whorled 
laterals they are irregularly platelike, covering 
almost the whole periphery of the cell. As the 
cells increase in size the chromatophores 
change through an irregular anastomosing 
stage to branched, linear shapes in the larger 
cells of the main axes. These linear chro- 
matophores tend to converge towards the nu- 
cleus (Fig. 2d). Carpospores and tetraspores 
contain chromatophores which form an irreg- 
ular, granular network. The nodal or banded 
appearance of the thallus is accentuated by 
the denser chromatophores in the small outer 
cells of the whorled laterals, giving a deeper 
colour to the nodal bands. In older axial cells, 
covered by corticating filaments, the chro- 
matophores are greatly reduced. Most cells 
contain numerous cytoplasmic granules, often 
concentrated around the nucleus, and at the 
cell junctions (Fig. 2d). 
Pyriform "gland” cells, with a thick mu- 
cilaginous wall, occur on cells of the whorled 
laterals (Fig. 2b, e) in all plants. These cells 
average about 30 fx in length and each con- 
tains several larger inclusions of varying but 
definite form (Fig. 2e). These may be the 
"monospores” referred to by Schmitz and 
Hauptfieisch (1897), but are probably com- 
parable to the gland cells of other genera 
of Ceramiaceae. 
The whole thallus is enveloped in a mu- 
cilaginous matrix, making it quite slimy. 
TETRASPORANGIA 
Tetrasporangia are produced in the upper 
parts of the thallus, on the outer end of cells 
of the third order of the whorled laterals. 
Only one tetrasporangium develops on a 
single cell (Fig. 2a, b). The sporangium is at 
first spherical, uninucleate, and sessile, at- 
tached by a thin cytoplasmic connection. It 
reaches 70-80 /x in diameter before division 
commences. The nucleus divides twice, and 
with four nuclei present the protoplast divi- 
sion commences at the periphery and pro- 
ceeds inwards, giving four uninucleate tetra- 
hedrally arranged spores (Fig. 2b). Meiotic 
figures were not seen in the material available. 
Accumulation of Floridean starch is indicated 
by red staining with iodine in tetrasporangia 
over about 50 ijl in diameter, the staining 
becoming deeper in mature spores. Mature 
tetrasporangia are about 80-90 }jl in diameter. 
SPERMATANGIA 
Male plants bearing spermatangia are not 
easily distinguished from sterile plants, but 
are slightly paler in colour and "rougher” in 
appearance. This is due to the spermatangia 
which are formed from the majority of the 
terminal cells of the whorled laterals. Each 
normal terminal cell bears a further two or 
three whorls of small cells, the outermost 
being the spermatangia. These spermatangia 
are 8-9 /x long, constricted in the centre, with 
a median nucleus and two prominent vacu- 
oles (Fig. 2f). Spermatangia are not formed 
from the occasional terminal cells which 
divide transversely. Spermatangia are 3.5-4 /x 
in diameter. 
FEMALE PLANT AND CARPOSPOROPHYTE 
In female plants, special branches, initially 
similar to young vegetative branches, occur 
at short intervals along the axis of main 
branches. Flowever, normal vegetative growth 
ceases with the development of carpogonial 
branches, which are produced either singly or 
in opposite pairs. Most commonly the third 
