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



25 



Fila erecta parce ramosa, 5 — 6/i lata, 

 cellulis diametro triplo vel 4 plo longioribus, 

 cylindricis, in parte superiori filorum cellulis 

 tenuioribus, 3 — 4;/ latis, chromatophorum, 

 ut videtur, parietale pyrenoide laterali 

 munitum continentibus. 



Sporangia monospora, fusiformia apice 

 truncato, sessilia aut pedicellata, sparsa 

 aut unilateraliter seriata, 4—5^ lata, 10 — 

 11 /ji longa. 



This small species was found upon 

 old leaves of Caiilerpa taxijolia. Only a 

 single tuft was met with growing in com- 

 pany with Acrochætium seriatum and other 

 small epiphytes. 



It forms a dense low tuft up to about 

 400,« high. 



The basal part consists of creeping 

 filaments (Fig. 11 d) fusing more or less 

 together but, it would seem, easily separ- 

 able. The cells in these filaments are Fig. 17. Acrochætium netro- 

 rather short, often nearly isodiametric but ^^'PJ^"^ f'^ H^'^^ents' ^'tli 

 much irregular in shape. From nearly all sporangia, d, base of the 



of these cells with the exception of those P A'a '-f' ^^^nÅ^^Kx^' ^' 



^ 4o0 : 1 ; a, 600 : 1). 



near the margin erect filaments arise. 



These (Fig. 17 a) are multilaterally ramified but not much so, 

 and taper somewhat towards the upper end (Fig. 17 c). They 

 consist of cylindric cells about 18 — 20 /j. long; in the basal part 

 these cells are about 5—6 ^ broad while those at 

 the summit are only 3 — 4//. 



The shape of the chromatophore was not clearly 

 visible, so far as I have been able to see it was 

 parietal with a lateral pyrenoid ; the last mentioned 

 was more visible in the sporangia (Fig. 18). 



The latter have a very characteristic shape 

 (Figs. 17 b, 18) ; they are fusiform with a truncate 

 p. g summit, about 4 — 5 fx broad and 10 — 11 /u long. 

 Acrochætium They are mostly sessile but often also pedicellate. 



netrocarpum f^ey occur more or less in a series or may be more 



nov. spec. '' "^ 



FUamentwith scattered. 



sporangia. 

 (About 

 800 : 1). 



This species has only been found once namely at Chri- 

 stianssted, St. Croix. 



