BROWN SEAWEEDS OF THE SALT MARSH. 277 
growing embedded in the soil of the marsh and presenting a coralline appear- 
ance ; and a spiral Fucus also growing without attachment, embedded in the 
soil, and a variety of Ше same Fucus which has a broad and much crinkled 
thallus. 
PELVETIA. 
Mode of Growth and Occurrence.—At Blakeney two forms of P. canaliculata, 
besides the normal attached form, were found. The first (text-figs. 2 & 3) is 
entirely without attachment, either to the soil or to the plants among which 
it grows. The plant is about the same size as when growing’on a stone, but it 
is usually more profusely branched. The most siriking characteristic feature 
is the curling of the younger parts of the thalius. This curling seems to be 
away from the ground as the plant rests in its natural position, and, together 
with the luxuriant branching, gives it a dense bushy appearance. Also the 
curled branches of neighbouring plants are interlaced as they lie on the 
ground, so that a more or less continuous matting is formed over the marsh. 
Pl. 8. fig. 2 is a photograph showing Salicornia europea growing with this 
loose Pelvetia. The colour of the unattached variety of Pelvetia is considerably 
darker than that of ordinary attached plants, varying from dark brown to 
olive-green. It is not displaced by tidal inundation. 
Reproduction.—This alga has been observed by Prof. F. W. Oliver at several 
seasons of the year, and the reproduction seems to be almost, if not entirely, 
vegetative, by means of budding from various parts of the thallus. Small 
tufts of such buds are shown at ж and В in text-fig. 2. Apparently the parent 
plant gradually dies away, leaving the younger shoots to occupy its position. 
After extensive search, a small fragment of unattached P. canaliculata was 
found, fruiting in the normal way, among the sterile plants on the marsh ; 
but it is quite possible that this was merely a fragment torn from the stones 
in the neighbourhood, where there is a zone of normal P. canaliculata. The 
same specimen also showed vegetative budding, as well as the receptacles, 
but the oceurrence of such budding is by no means uncommon in the 
ordinary attached plant. 
Relation of the loose Pelvetia to Fruiting Specimens.—The origin of this 
extensive matting of Pelretia is a matter of some interest. Along the north- 
western side of the tongue of dune and shingle which intersects the marsh 
(text-fig. 1, on right) there is a narrow zone, about 1 to 2 feet wide, of 
P. canaliculata attached to pebbles and fruiting in the normal way, repre- 
sented in the sketch-map (text-fig. 1) by a heavy broken line. This at once 
suggests itself as the original source of the Pelvetia on the marsh; but 
whether the loose form arose originally by the germination of oospores carried 
