

I12/X 



Fig. 120 Hortnosira banksii. A, portion of plant ( ^i). B, longi- 

 tudinal section of apex of plant, a = air-filled space. C, transverse 

 section of thallus at intemode ( ■ 150'. D^ longitudinal section of 

 apex. E, transverse section of apex. F, cuticle being shed (semi- 

 diagrammatic). (Aj Cj after Getman; B, D, E, after Oltmanns; F, 



original.) 



cuticle that bears the impressions of the cell outlines, this feature 

 perhaps being of significance when the problems concerning the 

 Nematophyceae are considered (cf. p. 302). The genus is mono- 

 typic, the single species, H. banksii, being confined to Austraha 

 and New Zealand where it grows on rocks and in tide pools of the 

 Uttoral belt in positions that are always exposed to the spray. 

 Although several varieties have been described, it has recentiy been 

 showTi that these are merely rather more distina representatives of 

 a range of ecological forms. Use of a statistical technique, the 

 discriminant function,^ has enabled these various ecological forms 

 to be differentiated (see also p. 410) (Fig. 121). 



^ This was based upon two measurements, bladder diameter and connective 

 length. 



213 



