MABINE ALGyE. 



47 



XVII. ZONARIA. 



Frond ribless, flat, fan-shaped. Root coated with 

 woolly fibres. 



1. Zonaria parvula. 



XVIII. Taonia. 



Frond ribless, irregularly cleft, somewhat fan-shaped, 

 marked with concentric lines. Sori on both surfaces of 

 the frond. Root coated with woolly fibres. 



1. Taonia atomaria. 



XIX. Dictyota. 



Frond ribless, dichotomous. Spores scattered irregu- 

 larly, or clustered. Root coated with woolly fibres. 



1 . Dictyota dichotoma. 



XX. Stilophora. 



Frond filiform, irregularly branched. Spores con- 

 cealed among moniliform threads. Root a small, naked 

 disk. 



1 . Stilophora rhizodes. 



2. „ Lyngbyei. 



