227 



Fam. XII. SCYTONEMEiE. 



Char. Algae for the most part branched^ rigid, or flaccid. 

 Cells globular or compressed. Colour either a dark olive 

 or a vivid (Bruginous green. 



The AlgcB 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 

 in drying, and the second division including species which 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 Kiitzing makes the type of his order Paraspermece, 

 an order characterized by its lateral sporules, and including 

 Lyngbyacece. and Calothricece, families which follow in his 

 arrangement the Scytonemece. 



Section i. Stigonjemsje. 



22. STIGONEMA^^. 



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

 tilaginous. Cells moniliform, arranged in transverse lines. 



Derivation. From o-Ttyoiv, dotted, and vrjfia, a thread. 



There is scarcely any necessity for this genus: the species 

 ;scribed 

 Hassallia. 



described in it would form a natural section of the genus 



1. Stigonema atkovirens Ag. 

 PI. LXVI. Fig. 1. 



Char. Filaments tufted, coarse. Branches slightly divided, 

 subacute. Rings mostly formed of three cells. 



Q 2 



