227 



Fam. xii. SCYTONEME^. 



Char. Algaj for the most j)art branched, rigid, or flaccid. 

 Cells globular or compressed. Colour either a darh olive 

 or a vivid ceruginous green. 



The Alga described in this family form two very distinct 

 sections ; the first section embracing those species which are 

 characterized for the most part by a rigid cartilaginous habit, 

 globular cells, a black or olivaceous colour, being lustreless 

 iu drying, and the second division including species wlilch are 

 not of a rigid habit, but whose filaments are flaccid, cells usu- 

 ally cylindrical, and colour a vivid green. The species of this 

 last section Klltzing makes the type of his order Paraspcrmece, 

 an order characterized by its lateral sporulcs, and including 

 LynglyacecB and Cahthricece, fixmllies which follow in his 

 arrangement the Scgtonemece. 



Section i. Stigoneme^. 

 22. STIGONEMA y^^. 



Char. Filaments tufted, branched, of irregular diameter, car- 

 tilaginous. Cells moniliform, arranged in transverse lines. 

 Derivation. From arLjcov, dotted, and vrjfia, a thread. 



There Is scarcely any necessity for this genus: the species 

 described In it Avould form a natural section of the genus 

 Hassallia. 



1. Stigonema atrovirens Ag. 

 PI. LXVI. Fig. 1. 

 Char. Filaments tufted, coarse. Branches slighihj divided, 

 subacute. Rings mosthj formed of three cells. 

 *Q 2 



