Notheia anomala is an obligate epiphyte commonly found on the abundant habitat-forming alga Hormosira banksii in intertidal areas throughout temperate Australasia The tight co-evolved relationship between these species is unique because: (i) Notheia is a true obligate epiphyte  which is uncommon in the marine environment  (ii) the order Fucales is over 70 million years old and includes over 10 families  but Notheia is one of few fucoid epiphytes  and (iii) phylogenetically close species are rarely so closely linked (Hormosira  the obligate host of Notheia  is also a fucoid)