G. SERTULARIA. 
85 
compressed ; ovaria nearly of an oval form, and bor- 
dered ; branches dichotomous, and in rows. 
European seas. 
CYPRESS-FORMED. 
17. Sertularia cupressoides . Cells scarcely pro- 
jecting, simple, and obliquely truncated; vesicles oval; 
branches dichotomous, articulated, and dispersed. 
White sea. 
MISENIAN. 
18. Sertularia Misenensis . Very branching, and 
dichotomous ; cells alternate, small, and diverging ; 
ovaria oval, pedunculated, and axillary. 
Mediterranean, near Misena. 
LICHEN. 
19. Sertularia lichenastrum. Stem pinnated 
and articulated ; cells imbricated in two rows. 
European seas. 
CLUSTERED. 
20. Sertularia racemosa . Stem upright, cylin- 
drical, and branching ; branches almost arched ; cells 
dispersed ; ovaria branching. 
Mediterranean. 
dusky. 
21. Sertularia fuscescens. Cells nearly opposite, 
and tubular ; ovaria approximate, small, and with 
three tubercles. 
Coast of Cornwall. 
SPIKED. 
22. Sertularia spicata. Stem tubular, panicled, 
and marked with rings ; branches very close, verticil- 
