KEY TO THE GENERA OF THE ATLANTIC 



COAST. 



OLIVE GREEN A&G/E. 



I. Frond leaf- hearing. 



Main stem and branches cylindrical, bearing 

 globular, stalked minute, air vessels, and 

 narrow, undivided, dotted leaves. General 

 habit arborescent. "Gulf- weed.'' Sargassum. 



II. Frond, flat, coriaceous or leathery. 



i. With Midrib, 

 (a.) Frond perforated. Agarum. 



(b.) Frond entire, stem bearing leaflets or 

 wings. A/aria. 



2. Without Midrib. 



(a.) Frond thick, leathery and large, dark olive 

 green or brown. "Kelp.'' L iminaria. 



(b.) Frond thinner and smaller, light green or 

 brown, from three to twelve inches 

 long. Punctaria. 



(r.) Frond narrow in proportion to length, 

 half-inch wide, eight to twelve in< hes 

 long. PhyUitis. 



(d.) Frond still narrower and constricted at 

 intervals. Hphon. 



