EUPHYCOPHYTA 



141 



known. They would appear to represent a transition from the Ecto- 

 carpalean type to the Dictyotalean type of reproduction, though 

 retaining Ectocarpalean morphology. Asexual reproduction takes 

 place by means of characteristic, large, motionless quadrinucleate 

 monospores which almost certainly represent unsegmented or 

 primitive tetraspores. Sexual fusion has not so far been reported 

 within the order. Recent work (Kornmann, 1953) has shown that 

 the genus Acinetospora^ formerly placed in this order, is properly a 

 member of the Ectocarpales. 



Tilopteridaceae: Haplospora {haplo, simple; spora, seed). Fig. 78 

 The plants, which arise from a basal disc, are filamentous, with 

 irregular pinnate branching from the main axes. The lower portion 

 becomes multiseriate by septation and then resembles Sphacelaria 

 but the growth is always intercalary. The sexual plants develop 

 intercalary, tubular, plurilocular gametangia which are produced 

 by the transformation of one or more cells of the main filament. 



Fig. 78 Haplospora globosa. A, portion of plant with uninucleate 

 sporangia, m (oogonia?), and plurilocular microgametangia, p. 

 B, plurilocular microgametangium. C, monosporangium with 

 quadrinucleate monospore. D, monosporangia. E, F, unilocular 

 sporangia (oogonia?). (A-Q after Oltmanns, D-F, after Tilden.) 



