404 



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



St. Jan: In the sound between this island and St. Thomas and in 

 the sea to the north of this island. 



Geogr. Distrib. : West Indies, Morocco, Mediterranean Sea, Canary 

 Islands. 



Coelarthrum Børgs. 



1. Coelarthrum Albertisii (Piccone) Børgs. 



Børgesen, F., some new or little known West Indian Florideæ, II 

 (Bot. Tidsskr., vol. 30, p. 189, 1910). 



Chylocladia Albertisii Piccone, Crociera del "Corsaro" alle Isole Madera 

 e Canarie del Capitano Enrico d'Albertis, p. 37, tab., fig. 3 — 5, 1884. 





Fig. 388. Coelarthrum Albertisii (Piccone) Borgs. 

 A, part of a plant (about natural size); B, part of a female plant (about 

 2:1); C, transverse section showing the diaphragm between the joints (10:1). 



As mentioned in my former paper this plant was at first 

 found at the Canary Isles by Piccone and described by him as 

 Chylocladia Albertisii. Referring to my above quoted paper with 

 regard to my reasons for considering this plant a representative 

 of a new genus, I shall here restrict myself to a short description 

 of the plant. 



Coelarthrum Albertisii forms small bushes about 4 — 5 cm 

 high. The thallus is nearly terete, articulate, hollow, repeatedly 

 dichotomously ramified (Fig. 389 A). The joints are largest in 

 the basal part, in my specimens oblong obovate of shape, about 

 1 cm long and V2 cm broad; upwards the joints become gradually 

 smaller and nearly spherical. Between the joints diaphragms are 

 present dividing the cavity in the interior into as many compart- 

 ments as there are joints (Fig. 389 C, 390 A). 



The membrane consists of a layer of rather large cells oblong — 

 rectangular when seen from the surface (Fig. 390 Z), £"), more 

 roundish-quadrangular in transverse section (Fig. 390 A, B, C.) 



