50 THE MARINE BOTANIST. 



lines, fringed with articulated filaments ; the margin 

 of the fi^ond rolled back. 



Fructification, Linear concentric sori bursting 

 through the upper surface of the frond. 



PADINA PAVONIA.— PEACOCK'S-TAIL 

 PADINA. 



Fronds tufted two to five inches high, stalked 

 or sessile, erect, broadly fan-shaped, either entire 

 or repeatedly and deeply cleft, all the divisions 

 being fan-shaped. The upper surface of the frond 

 is marked with regular bands, along which the 

 spores are placed in linear sori. The under part 

 of the irond is frequently covered with a whitish 

 powdery substance, and the texture of this portion 

 of the plant is leathery and thickened, while the 

 upper surface is delicately membranaceous and 

 transparent. Grows on rocks in shallow tide-pools, 

 a,t half-tide level-race. 



