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IV. Fucus. Linn. 



Frond dichotomous. Air-vessels innate and usually in pairs. 

 Mid-ribbed. Spores lateral or terminal. 

 F. vesiculosus, Linn. ; Common. 

 F. rtodosus, Lamouroux. 

 F. serratus, Lamouroux ; Newburyport. 

 F. Mackaii, Turner ; New York Bay. 



V. Himanthalia. Lyngb. — Name, Sea-ihong. 



Frond top-shaped. Receptacles very long, much forked from the 

 centre, strap-shaped. 



H. lorea, Lyngb. ; Massachusetts. 



Order II.— SPOROCHNACEJE. Harvey. 

 Inarticulate, olive-colored. Spores attached to jointed filaments, 

 free or joined in masses. Contains twoAmeiican genera, namely — 



I. Desmareslia. II. Arthrocladia. 



I. Desmarestia. Lamour. — Name from a French naturalist. 



Frond filiform or flat ; solid ; distichously branched. 

 1) aculeata. Lam. ; Rhode Island, Lynn, &c. 

 D. veridis, Mull. ; New York Bay and Sound. 

 D. Sp. ? or new ; Long Island Sound. 



II. Arthrocladia. Duby. — Name, a jointed branch. 



Frond traversed by a jointed tube. Filiform, nodose, the nodes 

 producing tufts of jointed filaments. Rare. 

 A. villosa, Hudson ; Wilmington, N. C. 



Order III.— LAMINARIACE.E. 



Inarticulate. Spores superficial, in patches, or covering the 

 whole surface. Usually strong fibrous roots. Contains three 

 genera, namely — 



I. Alaria. Greville. — Name, a wing. 



II. Laminaria. Lamour. — Name, a thin plate. 

 III. Chorda. Stackhouse. — Name, a cord. 



I. Alaria, Grev. 



Leaf membranaceous, with a hard midrib. The stem pinnated 

 with ribless leaflets, which form the leceptacles. 

 A. esculenta, Lamour ; Massachusetts Bayl 



II. Laminaria.' Lam. 



Foot stalk expanding into a broadish leaf. Leaf ribless. Spores 

 embedded in the leaf. 



L. taccharina, Lamour. ; Long Island Sound, &c. 



L, longicruris, Har ; Sioningion. 



L. fascia, Mull. ; JNew York Bay, &c. 



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