PHJEOPHYCE.E 



89 



The sori of unilocular sporangia are produced opposite 

 the whorls, and the obovate sporangia arise as lateral 

 outgrowths of filaments produced by the superficial 

 cells. 



Stilophora (of which S. rhizodes is British, North 

 Atlantic, and Mediterranean, and S. tuberculosa, like 

 Halorhiza, Baltic) has a filiform thallus with axial 

 strands of cells which grow in length by division of 

 the cells immediately below the apex, and a mantle 

 of tissue enveloping this 

 central axial tissue. The 

 mantle consists of a few 

 layers of parenchymatous 

 cells, and originates in the 

 branches of the axial series 

 below the growing-point. 

 The cells of the mantle 

 diminish in size towards 

 the exterior. Ultimately, 

 through the separation of 

 the axial tissue, the interior of the thallus becomes 

 hollow. It differs further from the above forms 

 and approaches the Chordariaccce in having both 

 unilocular (obovate) and plurilocular sporangia, the 

 latter with the loculi in one row. Both unilocular 

 and plurilocular sporangia arise as lateral outgrowths 

 of hairs produced by the superficial cells. 



FIG. 20. Stilophora rUizodcs. 

 Longitudinal section of growing 

 point. Highly magnified. (After 

 Keinke.) 



