Flora of Australia. 257 



Ertthrostachys prolifera (T.Ag.). J. White. (Algae. 

 Rh(jdomelaceae.) 



Encounter Bay, South Australia. D. Hussey. 



A new genus of Alga named by T. Agardh, but undescribed. 

 This specimen was sent to Major Reinboldt at Itzehoe, and re- 

 turned by him as a genus unknown to him, and also to the 

 Keeper of the Agardh Herbarium at Lund. It is hoped that by 

 publishing this description the search for further material of 

 this interesting plant may be stimulated. 



This specimen is purely vegetative, no trace of reproductive 

 organs being visible. It apparently belongs to the family 

 Rliodomelaceae. Frond stipitate, the stalk cylindrical, and in 

 this specimen about 5 inches long, and in its thickest portion 

 about half a line in diameter. The frond is prolilically branched, 

 the branches arising in lateral groups alternately along the 

 frond, at intervals of from one to two lines. These primary 

 branches are usually less than an inch in length, are filiform 

 and branch rather freely to form secondary branches alter- 

 nately. 



The secondary branches give off numerous short tertiary 

 branches alternately, which tend to become crowded towards 

 the tij), where the secondary branches become spirally swollen. 

 The tertiary branches soon after their origin divide usually 

 into two branches, which taper to a rather fine point. 



The whole plant is covered externally by a rather thick, 

 gelatinous sheath, the same material forming the intercellular 

 material. The tertiary branches are strongly articulate. 



The stalk of the frond, primary and secondary branches, is 

 solid, and composed of a large number of somewhat elongated 

 cells, about 3 to 6 rows of the more peripheral of which are 

 less regular and filled with highly coloured, apparently struc- 

 tureless contents, the cells tend to become more elongated 

 towards the centre, and are completely filled with granular con- 

 tents which are probably physodes and impart a cellular appear- 

 iince to the cell contents. The tertiary and ultimate branches 

 i\re onlv one cell thick. 



