Also called ‘Flat Wrack’, it is a dark olive-brown or greenish seaweed with a prominent midrib with no gas bladders. There are often pairs of swollen reproductive bodies on the tips of the frond branches. The fronds have a tendency to twist. Length 15 to 20cm.
Occurring on the upper shore, preferring sheltered to moderately exposed shores, where they cling to the hard surfaces. It also extends well into estuaries. It reproduces from July to September. A common and widespread species.
Photograph of Spiral Wrack (Fucus spiralis) taken June 2012, Llandudno, Wales. © Pete Hillman 2012. Camera used Nikon Coolpix P500.