F. Børgesen: List of species. 



453 



been able to discover the original germinating spore and the plant 

 may therefore be referred to group III of Born et ^). 



The erect filaments have at their base rather short cells; 

 higher up these grow gradually longer, the filaments at the same 

 time becoming thinner. 

 At the base of the fila- 

 ments the cells are 

 about 8/i, in their midd- 

 le about 5 fi, the upper 

 ends about 2 // only. 

 The cells contain a pa- 

 rietal chromatophore 

 and a parietal pyreno- 

 id ; upwards in the fila- 

 ments the chromato- 

 phore becomes less de- 

 veloped and is quite or 

 nearly absent in the 

 uppermost thin cells. 



The filaments are 

 scantily ramified bear- 

 ing short branches at 

 all sides; just as in the 

 case of the main axes 

 of the erect filaments 

 the main axes of the 

 branches are thickest 

 below with short cells, 

 having longer and thin 

 cells above. 



Upon the lowermost cells of the branches the sporangia 

 occur, placed mostly two together upon a short pedicel (Fig. 

 420 b). The sporangia are about 8 /i broad and 12 fi long. 



It is evident from this description that the plant shows great 

 likeness to the one found in Hypnea miisciformis. Nevertheless 

 some differences are present. For instance the erect filaments 

 grow taller and therefore proportionally more slender than those 



^) BoRNET, Ed., Deux Chantransia corymbifera Thuret. Acrochaetium et 

 Chantransia (Bull. Soc bot. France, Tome 51, 1904, p. XX). 



Fig. 420. Acrochætium repens Borgs. 



a, endophytic, basal filaments, b, erect filament 



with sporangia. (About 175:1). 



