This species forms relatively large green spheres in the walls of the tubular genus Blidingia, which are easily observed in surface view (Image A). In section the sphere is also clearly evident in the tube wall (Image B). Spheres can appear multicellular when they transform to reproductive development (reportedly zoospore production; Image C).
We have five records, two genetically verified (sequences were acquired accidentally while attempting to identify the host), with specimens from Haida Gwaii, BC, as well as NB and NL. To date they were found growing in Blidingia minima (Nägeli ex Kützing) Kylin, Blidingia marginata (J.Agardh) P.J.L.Dangeard ex Bliding Species 2, and Blidingia subsalsa (Kjellman) Kornmann & Sahling. I anticipate that this species is relatively common and grows in most, if not all of the species of Blidingia in our flora.
Image A. Whole mount of a Blidingia marginata (J.Agardh) P.J.L.Dangeard ex Bliding Species 2 specimen reveals the spherical endophyte (upper intertidal in Blidingia, Wallace Cove Lighthouse, NB; ENT10_Endo).