Unbranched golden to dark brown terete axes growing on Analipus japonicus (Harvey) Wynne (Image A). Individuals range in size from 4-10 cm tall and can be several mm wide. Their greater size distinguishes them from the determinate branches of the host, which are typically < 3 cm long. In long section thalli are hollow centrally surrounded by a loosely anastomosing network of medullary filaments, 1(2) cell layers of weakly defined subcortex and ultimately clavate assimilatory filaments, 3-5 cells in length (Image B), which branch and bear unilocular sporangia on the lowest cells only (Image C).
This species occurs widely in BC and in our experience is an obligate epiphyte of Analipus japonicus (Harvey) Wynne. All collections are from the mid to low intertidal and this species is fairly distinctive given its host partnership.
Image A. Press of a collection from the mid intertidal on Analipus japonicus (Harvey) Wynne (Wizard Island, Bamfield, BC; GWS009887).
Image B. Long section displaying anastomosing medullary network, poorly defined subcortex and outer clavate assimilatory filaments (GWS009887).
Image C. Close up of the clavate assimilatory filaments bearing unilocular sporangia on their lowest cells (GWS009887).