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THE SEAWEEDS 
Family BATRACHOSPERMACEAE Kylin 1928. 
Primary filament composed of a row of large cells, growing by means 
of a hemispherical apical cell. Whorls of densely branched lateral ramuli 
are produced at the nodes, giving a characteristic beaded appearance. From 
the basal cells of the lateral branches, cortical threads grow downward on 
the outside of the large axial cells, ultimately forming a complete cortex. 
After fertilization, short, branched, filaments of cells develop from the 
base of the carpogonia, the end cells forming carpospores. The gonimo- 
blasts lie embedded in mucilage between the assimilatory filaments, and a 
mass of protective filaments may be developed. 
Members of this family are mainly fresh water inhabitants. An uniden- 
tified species of Batrachospermum occurs in ditches at Mount Compass, 
South Australia. 
Family LEMANEACEAE. 
The species of Lemanea grow mainly in cool, clear mountain waters, and 
are usually yellow-brown, green-brown, or black in colour. They are often 
found in fissures, the thallus often consisting of a more or less upright 
system of branching filaments. In the development of a filament, a central 
cell is formed surrounded by at first four and later a number of cells, and 
eventually a central filament is present, separated by a space from a cortex 
one or two layers thick. 
The carpogonia 1 branch is formed from cells within the cortex, and is 
usually three celled, but the basal cell may branch and develop into another 
earpogonial branch. After fertilization the carpogonium develops inwardly 
a cell filament, which forms a much branched tuft of filaments, most cells 
forming carpospores. The carpospores are freed by breaking of the old 
filament or through an opening in the internode, but they may be pre- 
served in the mother plant for a time. 
Family HELM1NTHOCLAD1ACEAE Kylin 1928. 
Plants of moderated size, erect and coarsely branched, very mucoid, some- 
times partly calcified; structurally with an axial row of cells, or multi- 
axial with many filaments in the centre developing lateral assimilative 
branches of the “fountain” type; monosporangia present or absent; 
sexual reproduction by spermatangia borne in loose clusters on the ends of 
the assimilatory filaments; carpogenic branches borne variously on the 
assimilators, usually of three cells, the terminal being the carpogonium 
and auxiliary cells being absent ; cystocarp immersed among the assimi- 
lative filaments, without a definite pericarp, the gonimoblasts closely 
branched and the outer cells producing the carpospores. 
Nemalion Targioni-Tozzetti. Helminthocladia J. Agardh. H elmimthora 
J. Agardh. Liagora Lamouroux. 
