s A Field Guide to the British Seaweeds - NMBAQC

Ulva lactuca
A flat foliose plant two layers of cells thick
which can be seen by focusing up and down
under the microscope. Cells of various shapes
and sizes with no regular arrangement,
chloroplasts parietal sometimes filling the
whole cell other times appearing more band
shaped with one to several pyrenoids per cell.
Plant found throughout the littoral zone, but
commonly located on the lower littoral.
Morphological form a tough bright green broad
frond resembling a lettuce leaf. Other species
of Ulva may be found but U. lactuca is the
most common.
Chloroplast filling
the whole cell
Distinct two layers of
cells
Ulva found in natural habitat on the
lower shore mixed in with numerous
other brown and red species