THE MARINE ALG^ OF NEW ENGLAND. 101 



Var. SPH^ROCARPUS, Ag. 



Ultimate divisions of frond repeatedly forked, bearing very numerous 

 small receptacles. 

 Var. spiralis. 



Fronds short and spirally twisted. 

 Everywhere common between tide-marks. 



The varieties of this very common species are so numerous that it is useless to de- 

 scribe the greater part of them. The southernmost limit of the species on the eastern 

 coast is, as far as known, the coast of North Carolina, where it is reported to have been 

 collected by Rev. E. M. Forbes in Curtis's account of the botany in the Geological and 

 Natural History Survey of North Carolina. Fucus bicornis and F. microphyllus of De la 

 Pylaie appear to be merely forms of F. vesiculosus. The species with which the present 

 is likely to be confounded along our northern coast is F. evanescens, a broad plant, whose 

 midrib is only distinct in the lower part of the frond, and whose conceptacles are her- 

 mapbrodite, not dioecious, as in the present species. It fruits most abundantly in autumn 

 aud winter, but the fructification can be seen at any season of the year. 



F. ceranoides, L. ; Phyc. Brit., PI. 271. 



"Frond plane, coriaceo-membrauaceous, linear-dichotoinous, mid- 

 ribbed, without vesicles, margin very entire ; lateral branches narrower 

 than the principal divisions, repeatedly forked, level topped, bearing 

 fruit at their apices ; receptacles spindle-shaped or bifid, acute." (Ner. 

 Am. Bor., Vol. I, p. 70.) 



Xew York, Agardh; Europe. 



Tbe authority for the existence of this species on our coast is Agardh. Harvey had 

 never seen American specimens, nor have we ever found any. The species, judging 

 from herbarium specimens, resembles very closely Z- vesiculosus, especially var. lateri- 

 fructus, but is said to be thinner and to be destitute of air-bladders. It inhabits rather 

 brackish waters. 



F. serratus, L.; Phyc. Brit., PI. 47; Etudes Phycol., Pis. 11-14. 



Fronds dioecious, two to six feet long, midrib distinct throughout, 

 margin serrate ; bladders wanting j receptacles serrate, flattish, pointed. 



Newburyport, Mass., Captain Pike; Pictou, X. S., Rev. J. Fowler; 

 Europe. 



A very common species of Europe, but very rare ou our coast, being known in only 

 two localities. In the supplement to the Nereis it is reported from Newburyport, hav- 

 ing been once detected by Captain Pike, but not seen there since. The ouly other 

 locality is Pictou, where it was detected by Rev. J. Fowler, who sent specimens to 

 Professor Eaton in 1869. The species is easily recognized by its serrated margin, and 

 grows lower down in the water than F. vesiculosus. 



F. evanescens, Ag., Icon. Ined., PI. 13. {Fucus platycarpus^ in Far- 

 low's List of the Marine Algse of the United States.) 



Fronds hermaphrodite, one to two feet long, stipitate, midrib distinct 

 below, but widening and scarcely visible in the upper part, margin broad, 

 entire, somewhat wavy ; bladders usually Avnnting, when present much 



