F. Børgesen: Bhodophyceæ of the Danish W. Indies. 



33 



que secundatim ordinata, rarius plus minus 



sparsa. 



This species is an epiphyte especially 



upon Centroceras but it is also found upon 



other algæ e. g. Gracilaria, Chætomorpha, 



Caulerpa taxifolia etc. It forms small more 



or less dense tufts from 500 fx up to double 



this height. 



The basal part (Fig. 25 c, Fig. 26) con- 

 sists of short irregularly bent creeping 



filaments, fusing together in the middle 



into a small disc; it is composed of short 



rather thickwalled cells. 



From the cells in the middle of this 



disc several erect filaments gradually arise. 



The filaments consist in their lower parts 



of cells about twice as long as broad, 

 namely 8—10// broad and 16— 22/i long. 

 Upwards the filaments taper gradually, 

 reaching near the summit about 6 — 7 //, 

 while the length of the cells is mostly 

 about the same throughout the whole fila- 

 ment, but thinner branches occur in which 

 the cells are only about 4// broad while 

 on the other hand the length may reach 

 up to SO [J.. 



The erect filaments are branched often 

 from quite near the base, in the lower part 

 from all sides, higher up often quite uni- 

 laterally with the branches lying in the 

 same plane; the branches are again rami- 

 fied in the same way (Fig. 25 a) ; from this 

 the plant often gets an elegant pectinate 

 appearance. 



The cells contain a parietal chromato- 

 phore often with Jong prolongations along 

 the wall of the cells and with a large 

 lateral pyreiioid much protruding into the 

 interior of the cell (Fig. 28) ; in some speci- 

 mens the chromatophore is large covering riMum nov. spec. 

 nearly the whole wall with the exception ^^^^.''^t' witV 'spi^angi^^' 

 of a small part near the ends of the cells; A(bout 135 : l). 



Dansk Botanisk Arkiv, Bd. 3. Nr. 1 (1915). 3 



Fiff. 27. Acrochætium se- 

 Habit 



