320 



Dansk Botanisk Arkiv, Bd. 3, Nr. 1. 



longi, in parte basali ca. 24 |u crassi ad apicem filorum versus gradatim 

 longiores, apice rotundato, ca. 8 j.i lato. 



A rather large and elegant plant of dark rosy-purple colour when 

 dry and reaching a heigth of up to 20 cm. The specimens are much 

 branched on all sides forming dense tufts; the branchlets become 

 shorter towards the summit giving the plants a pyramidal outline. 



The upper parts of the 

 branches and branchlets are 

 covered by ramuli. These are 

 especially densely placed at the 

 ends of the branchlets giving 

 them an ocellate appearance. 

 The basal part of the branchlets 

 and branches are bare. The 

 principal branches are about 1 

 mm thick, while the branchlets 

 are only about 100 jii thick. 



The cortical layer is incom- 

 pletely developed upon the 

 younger branches and branch- 

 lets being here limited to a 

 single or a few hyphæ running 

 down in the furrows between 

 the pericentral cells; upon the 

 thicker main filaments, on the 

 other hand, a coherent cortical 

 layer is found. 



The plant has five pericentral 

 cells surrounding a rather large central cell. The pericentral cells reach 

 a length of about 300 — 400 ^ in the younger parts of the branchlets. 

 The ramuli are placed with a divergency of about ^ ; they are slen- 

 der and long, often reaching a length of 4 mm. At their base they have 

 a large subquadratic cell, about 50|ii broad and 60 — 70 ju long, partly 

 immersed in the main stem (Fig. 323 a). The cells in the ramuli are shor- 

 ter and thicker at their base, longer and thinner upwards. In specimens 

 of my collection no. 1842, upon which I especially have based my exa- 

 mination, the ramuli were about 24 |a broad in the basal part and their 

 filaments had nearly the same breadth somewhat higher up, but then 



Fig. 323. Dasya caraibica nov. spec. 



Ö, part of the thallus, with two young 



plants of Acrochætium opetigenum Borgs. 



b, summit of a plant. 



{a, about 60 : 1. b, about 260 : 1). 



