100 KEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



Am. Bor., Vol. I, p. 68. — Fucodium nodosum, J. Ag. — Ozotliallia nodosa, 

 Dene. & Thuret. — AscopliyUum nodosum, Le Jolis; Etudes Phycolo- 

 giques, Pis. 18-20.) 



Fronds dioecious, one to five feet long, coriaceous, compressed, sub- 

 dichotomous, margin distantly toothed; air-bladders oblong, broader 

 than the frond ; receptacles ovoid or ellipsoidal, terminating short lat- 

 eral branches, which are borne either solitary or clustered in the axils 

 of the teeth. 



Common between tide-marks from New Jersey northward; Europe; 



Arctic Ocean. 



One of our most common species, easily recognized by the large bladders in the con- 

 tinuity of the frond, which is thick and narrow and entirely destitute of a midrib. 

 The fruit is found in lateral branches in winter and spring, and in June the receptacles 

 fall off and are sometimes found in immeuse quantities covering the bottoms of tide- 

 pools. 



FUCUS, (L.) Dene. & Thuret. 



(From <{)vkoc, a sea-weed.) 



Fronds dioecious or hermaphrodite, attached by a disk, plane, costate, 

 dichotomous, margin entire or serrate, often furnished with air-blad- 

 ders; receptacles terminal, continuous with the frond; spores eight in 

 a mother-cell. 



In the beginning of the present century the name Focus was used not only to desig- 

 nate all the plants included in the present order, but was applied to all marine algro. 

 Since that date the word has been used in a more and more restricted sense, and is 

 now only applied to those members of the Fucacew in which the spores are in eights 

 and in which the frond is plane and costate. In some of the species, however, the 

 midrib is rather indistinct. Most of our species are very abundant and very variable, 

 and older writers have described a.3 species a good many forms which are now con- 

 sidered to be merely varieties. Hence the synonymy of the species is in confusion, 

 although our species, none of which are peculiar to America, can be referred to definite 

 European forms. The species described by De la Pylaie in the Flore de Terre-Neuve 

 are most of them to be referred to older species. The New England species naturally 

 fall into two different groups. In the first, of which F. vcsiculosus is the type, the fronds 

 are dioecious and the midrib distinct throughout. In the second, represented by F. 

 eranescens, they are hermaphrodite and the midrib indistinct. 



F. vesiculosus, L.; Phyc. Brit., PI. 204; Etudes Phycol., PI. 15. 



Fronds dioecious, six inches to three feet long, stipitate, midrib dis- 

 tinct throughout, margin entire, often wavy; bladders spherical or 

 slightly elongated, usually in pairs ; receptacles swollen, ellipsoidal or 

 oval, often forked. 



Exs. — Algre Am. Bor., Farlow, Anderson & Eaton, No. 109. 



Var. laterifructus, Grev. 



Lateral branches, which bear the receptacles, narrow and densely 

 dichotomously flabellate. 



