EUPHYCOPHYTA I51 



erect filament of the macroscopic plant arises. There is thus an 

 alternation of morphologically distinct generations in this species. 



Chordariaceae : Eudesme (well-binding). Fig. 82 



This genus is very closely allied to Castagnea and by some 

 workers the two genera are treated as one. The branched mucila- 

 ginous plants are densely hairy and differ from Mesogloia funda- 

 mentally in the presence of more than one central strand in the 

 medulla, though there are other developmental differences as well. 

 In the young plant^the erect filaments arise from the centre of the 



'■N^DULLA- 



Fig. 82 Eudesme virescens. A, plant. B, diagram to illustrate 

 thallus construction (multiple strand type). C.H. = colourless hair, 

 P./i. = primary assimilator, 5".^. = secondary assimilator, S.C.= 

 secondary cortex, S.Sc— secondary subcortex, ^.Af. = secondary 

 medulla. C, apex ( x i6o). D, thallus with branch and corticating 

 filament ( x 75). E, unilocular sporangia. F, plurilocular sporangia. 

 (A, E, F, after Oltmanns; B-D, after Parke.) 



