peacock's tail

noun
  1. a handsome brown seaweed, Padina pavonia (though coloured yellow-olive, red, and green) whose fan-shaped fronds have concentric bands of iridescent hairs
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012