OF SOUTH AUSTRALIA. 
171 
Rhabdonia nigrescens Harvey. 
Frond filiform, irregularly very much branched, virgately similarly 
decompound, ramuli constricted at the base, apices acuminate. Infra- 
cortical cells in one layer. Substance rather rigid. Colour dusky-purple. 
Height 10 cm. to 14 cm. 
South Australia (Encounter Bay, Eastern Bays), Victoria, Tasmania. 
Rhabdonia coccinea Harvey. 
Frond stipitate, dendroid, very much branched and bushy, alternately 
pinnate decompound, ramuli attenuated at base and apex. Infracortical 
cells in several layers. Substance cartilaginous and rather soft. Colour 
when growing is a deep full-red, which becomes a brilliant crimson if the 
plant is steeped in fresh water. Height 15 cm. to 30 cm., about 1 mm. 
thick. 
Western Australia, South Australia (Investigator Strait, Eastern Bays), 
Victoria, Tasmania. 
Fig. 42 .— -Rhabdonia coccinea : a, plant; b, ramulus 
with an imbedded conceptacle; c, cross- 
section of the frond; d, a tetraspore; e, 
cross-section of a conceptacle; f , one of the 
spore threads removed. (After Harvey.) 
