44 THE MARINE BOTANIST. 



CHORDA LOMENTARIA. — CONSTRICTED 

 CHORDA. 



Fronds constricted at intervals, as if tied; 

 slig'htly inflated in the part between each of the 

 contractions. From three to sixteen inches in 

 length, not half an inch in breadth; narrower at 

 each end. Substance soft and flaccid. Colour 

 brownish or yellowish olive. Grows on rocks and 

 stones between high and low water-marks. Annual. 

 Summer and Autumn. Not uncommon. 



DICTYOTACE^.— DICTYOTA TRIBE. 



Marine plants of an olive-green or olive-brown 

 colour and membranaceous substance, rarely coria- 

 ceous or cartilaginous, and scarcely at all juicy, 

 with a highly reticulated structure. Fronds va- 

 rious in form, round or flat, simple or branched, 

 without nerves or veins (excepting Haliseris), often 

 divided in a fan-like shape. Fructification. Spores 



