EUPHYCOPHYTA 



231 



serpensy^ and the Japanese species B. hamifera and Trailliella intri- 

 cata. Other representatives may be strictly diplobiontic (see p. 314) 

 since tetraspores have been reported in Delisea pulchra and D. 

 suhrii. 



Helminthocladiaceae: Liagora (after one of the Nereids). Fig. 

 127 



The axial portion of the thallus contains large cells with which 

 are intermingled narrower rhizoidal cells. Chalk is deposited to a 

 greater or lesser extent on the outside of the thallus so that the 

 plants are whitish in appearance. The principal interest of the genus 



Fig. 127 Liagora. A, carpospores of L. viscida ( x 320). B, carpo- 



spores in fours in L. tetrasporifera ( x 320). C, life cycle of L. 



tetrasporifera. (A, B, after Kylin; C, after Svedelius.) 



is that in four species the carpospores divide to give four spores 

 which must presumably be regarded as tetraspores. Although no 

 cytological evidence is available it is presumed that meiosis is 

 delayed to the time when the carpospores divide. There is thus no 

 independent tetrasporic diploid generation. This feature was first 

 discovered in L. tetrasporifera, an inhabitant of the Canary Islands. 

 A similar state of affairs has more recently been recorded for other 

 species of Liagora and for Helminthocladia hudscni. 



Chaetangiaceae : Scinaia (after D. Scina). Fig. 128 



This is a widespread genus with its home primarily in the north- 

 ern hemisphere, the commonest species, S. furcellata, being 



^ This is now known to be diploid (Magne, i960). 



