s A Field Guide to the British Seaweeds - NMBAQC

Desmarestia aculeata
Frond often quite narrow, generally
less than 2mm, flattened, coarse and
reddy brown in colour. The long main
axis is highly and regularly alternately
branched and can grow up to 180cm.
Side branches may be quite long but
in older plants branchlets appears
short, spine-like and look serrated.
Found most frequently in the lower
littoral particularly in sandy or
unstable substrate bottomed pools
Desmarestia in its natural
habitat, with a distinct
serrated appearance in
older plants and with the
long main axis clothed in
long branchlets as seen in
younger plants
Dictyosiphon foeniculaceus
Plant quite fine and delicate and light
brown in colour. Branches very irregular
and generally from main axis appearing
as straight thick filaments or filiform and
growing up to 70cm long. Filaments
often have an all-over covering of fine
hairs. Found most frequently in the mid
littoral area within wide shallow
rockpools often with sandy bottom. May
be confused with Chordaria sp.
Dictyosiphon in natural habitat