This wrack has no air bladders, and can easily be recognised by the saw-like edges to its leaves. This weed can withstand very short periods of drying out, and is submerged for most of the time. It does not extend much below the low water mark - this is where the kelp takes over.
Serrated Wrack (Photo: Sue Scott)
Serrated wrack is exposed to the air for only a short time each day .
by Paul Tyler