I found a seaweed at low water in rock pool in North Devon - very delicate about 3 inches high with bright blue tips to fronds which colour was only visible when viewed from certain directions. The coloured part approx 1 x 1.5 mm. The rest of the plant being brown .Can anyhone identify this ? Stan Hill.
It does sound like Chondrus crispus; there's an example showing the sheen at http://www.ispot.org.uk/node/272304 , & collins seashore guide says "tips may have a violet irridescence when in water". Jen's 2nd example also shows another sp's with similar irridescence, Mastocarpus stellatus ; & a 3rd example is the rainbow weed, Drachiella spectabilis, at http://www.marlin.ac.uk/speciesinformation.php?speciesID=3204 .These are all in the class Red weeds, though, eg, chondrus crispus can be green or even yellow in good light conditions.