s A Field Guide to the British Seaweeds - NMBAQC

Porphyra species
These plants are foliose and very membranous, thin and polythene-like, tending to be quite elastic.
They are mostly brownish red in colour with various morphological forms but they all tend to be
unbranched although some fronds may be highly torn. Species may be differentiated by the location
of their basal attachment and preferred habitat including position on the shore and host species. P.
umbilicalis is characterised mainly by its central holdfast from, forming a rosette like frond and is
located throughout the littoral mainly on open rock surfaces. P. leucosticta is a much smaller plant,
often quite delicate, pink-red in colour and is found growing epiphytically on other algae particularly
on the fronds of Fucus sp. attached by a basal holdfast. Also found growing throughout the littoral.
P. umbilicalis with
rosette appearance and
central holdfast
P. umbilicalis in its
natural habitat growing
on open rock surfaces
P. leucosticta cellular arrangement
and found growing on Fucus sp.