OF SOUTH AUSTRALIA. 
P. simpliciuscula Crouan = Ophidocladiis simpliciuscidiis (Crouan) 
Falk. 
P. callithamnion (Sond.) = Heterosiphonia callith amnion (Sond.) 
Falk. 
CHIRACANTHIA Falkenberg. 
Fronds erect, terete, laterally branched. Branches elongate, poly- 
siphonous, at length showing dorsiventral construction. Ramuli in lower 
part covered with aculiform ramelli. Axis polysiphonous, four pericentral 
cells, soon evolving a parenchymatous cortex. Cvstocarps single on short 
ramuli. Tetraspores nidulating in thick torulose stichidia, in a single spiral 
series. 
Chiracanthia vaZida (J. Ag.) Falkenberg. 
= Polysiphonia valida J. Agardh. 
Frond 15 cm. to 25 cm. long, pinnate, irregularly branched, the ramuli 
and ramelli alternate as far as the apices which are corticate and have no 
ramelli. The ramelli are short and distantly spaced in a congested subquar- 
rose mass, on a short stem. The ramelli are rigid, subulate, articulate and 
polysiphonous. Cystocarps pedicellate, subterminal, globose, with a 
prominent orifice. Dark-red, drying black. 
South Australia (Investigator Strait, Eastern Bays), South Coast 
generally. 
Chiracanthia arbor ea (Harv.) Falkenberg. 
Fronds 20 cm. to 50 cm. long, dendroid, excessively branched, opaque in 
all parts; main stem about 2 mm. in diameter, attenuated upwards. 
Branches spreading to all sides, bushy, several times decompound, all the 
divisions erecto-patent, inserted in an irregularly spiral order. Ramuli 
spine-like, very minute and closely set, with two to three incurved, sub- 
falcate teeth at the extremity. Cystocarps ovate, on long stalks, densely 
cellular. Colour dark-brownish or brownish-red. Substance tough. 
South Australia (Eastern Cove (Kangaroo Island)), Tasmania. 
Subfamily Pterosiphonieae Falkenberg. 
KEY TO THE GENERA. 
a. Pericentral cells four; fronds consisting of long 
branches in the one plane, irregularly lobed, 
below decumbent, above erect . Pollexfenia Harv. 
aa. Pericentral cells six ; fronds erect, distichously 
branching, branches tall Dictymenia Grev. 
POLLEXFENIA Harvey. 
Fronds plane, membranaceous, rose-purple, expanded, ecostate or with a 
median costa, lacerate, areolate, formed of polygonal cells. Pericentral 
siphons four. Cystocarps arising from the frond, ovate, osteolate, pericarp 
thick, carnose, sessile or pedicellate; carpospores pyriform. Stichidia 
obovate-oblong, subarticulate ; tetrasporangia alternately disposed. 
