BROWN SEAWEEDS OF THE SALT MARSH. 289 
belong to the same species, the differences between them being precisely the 
specific differences between F. spiralis and F. vesiculosus. 
Whether either of the unattached Рис’ merit the rank of a species, distinct 
from the one whence they are derived, is another question which I am not in 
а position to answer. Sauvageau considers the French. Fucus as a distinct 
species, F. lutarius, and suggests the name F. volubilis, originally given by 
Hudson for the English one. As the plant has so many different forms and 
such a wide range, it may be convenient, for the present at any rate, to follow 
this suggestion instead of multiplying the varieties of F. vesiculosus. If the 
two plants are found later to be merely varieties of F. spiralis and F. vesi- 
culosus respectively, it would be well to represent them as F. spiralis, var. 
lutarius, and К. vesiculosus, var. lutarius, to indicate the very great similarity 
between them. It is extremely interesting to find two separate species giving 
rise to forms so nearly identical, that, without the receptacles, it is impossible 
to tell certain specimens apart. 
Diagnoses of the Varieties described. 
PELVETIA CANALICULATA, var. LIBERA, S. M. Baker, var. nov. (Figs. 2, 3.] 
Plant not attached in any way, from 10-15 cm. in length, producing 
numerous adventitious buds from various parts of the thallus. Frond possess- 
ing the characteristic channelled form of P. canaliculata, profusely branched 
by dichotomy, the growing ends much curled, dark brown or olive-green in 
colour. Receptacles not known with certainty. 
Hab. Among the higher plants, notably Salicornia europea, of sheltered 
salt marshes, Blakeney, Norfolk. 
P. CANALICULATA, var. CORALLOIDES, S. M. Baker, var. nov. [Fig. 4.] 
Plant embedded in mud, from 1-4 ст. in length, producing adventitious 
buds from lower parts of thallus. Frond channelled, branching sparse, 
thallus somewhat curled. Receptacles unknown. 
Hab. Sheltered salt marshes, Blakeney, Norfolk. 
Fucus voLUBILIS, Huds.  [Figs. 5, 6, 8.] 
Plant not fixed by a disc, embedded in mud or unattached, from 4-80 ст. 
Vesicles numerous in the larger plants, but often absent or few in the smaller 
ones. Numerous adventitious buds produced from the base of plant. Frond 
much spirally twisted, from 1-8 mm. broad, provided with numerous crypto- 
stomata on the margins and over the tip of shoot. Receptacles elongated, 
oblong or almost pointed, occurring at the ends of the fronds, and hardly 
broader than the rest of the thallus, turgescent, with or without mucilage, 
