OF SOUTH AUSTRALIA. 
149 
spinulose or papillose; thallus structure net-like. Cystocarps immersed in 
the thallus, central or almost superficial, with a common nucleus of many 
spores more or less distinct. Tetrasporangia in sori of circular outline, 
everywhere in the frond in a sub-cortical position. 
Iridophycus australasica (J. Ag.) comb. nov. 
Frond large, to 50 cm. long, stipitate, lanceolate, oval or dilated above, 
margin entire, slightly undulate or folded, or with small leafy unequal 
inflations. Cystocarps common, immersed in the frond. Tetraspores 
cruciately divided, nidulating in sori towards the centre of the frond. 
Colour purplish-red. 
Southern Australia (Robe in South Australia) and Tasmania. 
GIGARTINA Stackhouse. 
A world-wide genus, with 15 Australian representatives. The contours 
vary greatly in the different species. The structure shows two strata of 
cells, the medullary of cylindrical, articulated filaments, anastomosing into 
a very close network, the cortical of moniliform, vertical, dichotomous fila- 
ments set in firm gelatine. Cystocarps external, globose, containing within 
a mass of closely interwoven filaments, a compound nucleus consisting of 
many confluent nuclei or masses of roundish-angular spores. Tetra- 
sporangia collected in dense sori lodged beneath the superficial cells. Four 
species are recorded from South Australia. 
Gigcirtina Muelleriana Setchell and Gardner. 
Frond terete, dichotomous-fastigiate, flabellate, segments and pinnules 
obtuse, solidly cartilaginous. Cystocarps on the flat face of a ramulus, girt 
by the elevated margin of the pericarp. Sori in the upper segments. 
Height 8 cm. to 15 cm., 2 to 3 mm. thick. Colour fleshy-yellow. Grows on 
reefs near low water. 
South Australia (Eastern Bays), Victoria, Tasmania. 
