Dumontia contortaDumontia contorta is a relatively small epiphytic algae of the sea-shore.DescriptionThe thallus grows from a discoid holdfast to a length of about. The fronds branch irregularly and sparingly. The branches are hollow, soft and twisted, dark reddish brown in colour which bleach towards the tips, they clearly taper at their junction.ReproductionThe plants are dioecious with microscopic spermatangia, carposporangia, and tetrasporangia developing in the surface layer, cruciate.HabitatGenerally epilithic in rock pools of the littoral zone.DistributionCommon around the British Isles. Europe from Russia to Portugal and Canada to United States. In the NW Pacific and Alaska.