582 Howe: Phycological studies 



upon the use of this historic collection did not permit any attempts 

 to determine whether the plants are synoicous or dioicous, but one, 

 at least, of the two, is, in our opinion, very clearly a rather small 

 specimen of the typical Fuciis Areschoitgii Kjellm. This specimen 

 is lo cm. high, the branches are somewhat contorted and 4-6 

 mm. broad above, the distinct costa alone persisting in most of the 

 lower half; the receptacles are ovate, obovate or suborbicular, 

 and 5-8 mm, long. It evidently represents a form of the synoi- 

 cous species which on the eastern coast of North America is com- 

 mon from Maine to Newfoundland and doubtless ranges farther 

 north ; it is confined to a rather narrow zone near the high-water 

 mark. Specimens illustrating this form from Cape Rosier, Maine, 

 were issued as no. 2j^ of the Phycotheca Boreali-Americana of 

 Collins, Holden & Setchell under the name Fitcus Arcschoiigii 

 Kjellm, The other Linnaean specimen cannot be so confidently 

 determined without dissection, yet we have little doubt that it also 

 represents a condition of the same synoicous species. This is a 

 larger, uncontorted plant, with more elongated receptacles and more 

 conspicuous cryptostomata, and the wings are more persistent be- 

 low ; it is about 20 cm. high, the even-topped branches are 4-8 

 mm. wide, the verrucose receptacles are 8—20 mm. long, mostly 

 2-3 times as long as wide, though one or two are suborbicular. 

 This appears to exemplify a form of the species which in North 

 America is rather more southern in its range than the other, being 

 not uncommon near the high-tide line in Long Island Sound 

 within the limits of New York City. This more southern form 

 occasionally approaches Fucus platycarpiis Thuret in habit, and 

 specimens from Marblehead Neck, Massachusetts, were distributed 

 under that name in the Phycotheca Boreali-Americana, no. iij2 ; 

 however, we have seen no American specimens in which the re- 

 ceptacles are as pronouncedly lateral as in the typical F, platy- 

 carpiis of northern France. The larger forms oi Fticus spiralis are 

 sometimes imitated by certain evesiculose conditions of F. vesicii' 

 ' los/is, but can be distinguished by being always synoicous and 

 usually also at sight by having more strongly verrucose and more 

 margined receptacles. It grows typically in a higher zone on the 

 rocks than does F. vesiculosits. Vesicular inflations are occasion- 

 ally present, but they are much elongated and irregular in form 

 and position. 



