EUPHYCOPHYTA 



77 



waste material. The cellulose walls are frequently thickened by 

 parallel or divergent stratifications, whilst each septum between 

 the cells may also have a single large pit which is penetrated by a 



2~0 

 4~0 

 6~0 

 8"0 



GELATINE ^. 



•COTTON WOOL IN 



Fig. 41 Trentepohlia. A, B, T. mantis-tabulae with pectin caps. 

 C, T. mantis-tabulae, cell structure. c=cap, /= innermost layer of 

 cell wall. D-F, types of chloroplast. G, chloroplast in T. ialithus. 

 H, I, T. umbrina fragmentation of prostrate system. J, threads of 

 T. aurea bearing sporangia (5). K, T. umbrina, sporangia. L, M, 

 two stages in the development of the 'funnel' sporangium in T. 

 annulata. N, graph showing decreasing water contents of Trente- 

 pohlia, gelatin and cotton-wool on drying. O, P, T. umbrina, detach- 

 ment of stalked sporangium, i.r. = inner, a.r. = outer thickening oi 

 sporangial septum. Q, mature 'funnel' sporangium, T. annulata. 

 R, S, gametangia of T. umbrina. (A-G, J, L, M, O-Q, after Fritsch; 

 H, I, K, R, S, after Oltmanns; N, after Rowland.) 



protoplasmic strand. The cells are uninucleate when young and 

 multinucleate when old, but the presence of the pigment makes the 

 nuclei extremely difficult to distinguish. Vegetative reproduction 

 is through fragmentation, whilst other means of reproduction are 

 to be found in three different types of sporangia: 



