OF SOUTH AUSTRALIA. 
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Subfamily Plocamieae (Reichb.) Kutzing. 
The characters are those of the single genus Plocamium. 
PLOCAMIUM Lamouroux. 
Fronds erect, narrowly linear, more or less compressed, the rami and 
ramuli spreading distichously in one plane. Membranaceous, not gelatinous 
or mucous* The interior cells longitudinal, oblong, the cortical cells 
roundish-angular, filled with red endochrome. The primary branching 
alternate with wide angles. The rachides of rami and ramuli are fringed 
with characteristic series of ramelli arranged alternately on each margin 
of the rachis. The ramelli are in pairs or there may be three, four or more 
in a secund or pectinate series, the lowest simple, the rest pinnulate and 
more or less decompound. Cystocarps and tetrasporangia on different indi- 
viduals. Cystocarps single, sessile on the margin of the pinnule, or 
aggregated in the axils, with a thick pericarp, the spores carried on thin 
paniculately branching threads without evident placenta. Tetrasporangia 
zonately divided in two longitudinal series in the sporophylls, modified 
ramelli; the sporophylls borne on the ramuli, then stellately or pinnately 
branched, or aggregated in the axils and then simple linear, arcuate. 
Antheridia evolved in superficial sori, of minute hyaline cells. Colour red 
of various shades. From the elegance of their fronds and the richness of 
their colour the plants of Plocamium are strikingly attractive. 
A genus occurring in the temperate seas of both hemispheres, but having 
its headquarters in the Southern Ocean, the Cape of Good Hope, Australia, 
Tasmania, and New Zealand. P. coccineum the favourite of British 
collectors, closely allied to our P. leptopkyllum if not identical with it, has 
been gathered at Cape Horn and by the Mawson Expedition in Common- 
wealth Bay of the Antarctic Continent. Of the 30 species described 11 are 
Australian. All have been gathered in South Australia except P. 
patagiatum, so far recorded from Tasmania only. They grow on the rocks 
in fairly deep water near the land. 
