336 DR, SARAH М. BAKER AND MISS М. Н, BOHLING ON 
form either to the smallest Blackwater Fuci or to the Clew Bay Fucus, or 
lie intermediately between them ; and there can be little doubt that they 
are all varieties of the same plant. References to the literature will be 
found with the diagnoses on p. 353. 
According to these data, all the English Fuci which have hitherto been 
described from salt marshes, except the very distinct F. spiralis v. nana, 
seem to be derived from F. vesiculosus rather than from F. spiralis. The 
\ 
e А 
у, E 
mS MP à & 
Fp 
Ета. 7.— Fucus vesiculosus megecad limicola ecad volubilis. + nat. size. 
Large form with vesicles and irregular bladderlike swellings, 
Virley Channel, Blackwater, Essex. 
one remaining possibility was that F. ceranoides might have been responsible 
for the parentage of some of the non-vesicled forms. This has now been 
ruled out of court by the appearance of an undoubted marsh variety of 
К. ceranoides, which will be deseribed in due course, and which is quite 
distinct from all these forms (р. 340). These marsh Fuci form one con- 
tinuous series; but for the sake of convenience they will be divided into 
three groups: the large spiral forms into the volubilis group, the turf-like 
forms, known generally as ‘ Fucus balticus,” into the cespitosus group, and 
the filiform forms into the muscoides group—all being varieties of F. vesi- 
culosus, L. A further discussion of the nomenclature follows оп p. 346. 
