s A Field Guide to the British Seaweeds - NMBAQC

Special features that need to be considered in making identifications
• Chloroplast morphology in cells (compound microscopic examination).
Parietal
Band/ ribbon shaped
Reticulate
o Parietal – forming a cylinder around the cell inside the cell
wall
o Axile – passing through the middle of the cell cavity
o Simple – a non-perforated plate or cylinder
o Band/ribbon shaped – a girdle almost completely encircling
the cell
o Discoid – often many discs per cell
o Reticulate – a network – sometimes made up of lots of
filaments of chloroplast material or sometimes formed by
lots of perforations and lobes on a parietal cylinder
• Pyrenoids –centre of formation of storage product in the chloroplast –stains
blue-black with iodine in potassium iodide in green algae only because starch
is the storage product. There may be a single or many pyrenoids per cell found
in or extending from the chloroplast.
Pyrenoids
Reduced species list identification guide as required by the Water Framework Directive 14