174 



NOTES ON AUSTRALIAN MARINE ALG^E, ii.* 

 Descriptions of Four New Species. 



By A. H. S. Lucas, M.A., B.Sc. 



(Plate vi.) 



L a v r e n'cia Lamour. 



LAURENCIA INFESTANS, Sp.llOV. 



Habitat.- — Covering large areas of the surface of the fronds of 

 Ecklonia radiata var. exasperata, and extending around the 

 coarse spinules of the frond. Manly, N. S. Wales. 



Attachment simple at the base of the frond, aided by nearly 

 sessile discs growing from the under surface of the creeping 

 branches and branchlets. Discs circular, of diameter greater 

 than that of the branch, formed of very narrow, colourless, 

 radiating cells. Habit simple (young) or with few main branches 

 diverging from the attachment, some erect, others horizontally 

 creeping. Extent of the frond, about 1 cm. Rranches pinnate, 

 bearing alternate patent ramuli, proceeding nearly at right angles 

 to the ramus. The ramuli for the most part constricted a little 

 above the base, linear, obtuse, the apices almost truncate, with 

 shallow, median foveola. Erect branches rounded, creeping, 

 compressed. Structure: in cross-section two strata of cells, 

 cortical of smaller, densely coloured, rounded cells, interior of 

 larger, oblong-angular, less deeply coloured cells; all the cells set 

 in gelatine. All the cells are elongated in axial direction. 

 (JuJour dull red, becoming darker on drying. Tetrasporangia 

 immersed in the apical region of the ramuli, rarely extending 



* Continued from Vol. xxxviii., 1913, p. 00. 



