Plants occur as little clumps of bright green feathery fronds reaching about 10 cm in height (Image A). The main axes are obvious and give rise to opposite paired branchlets, which are constricted at their base, in a regular pinnate fashion (Image B). Attachment is by a mass of basal rhizoids (Image C). Individuals are coenocytic, i.e. they lack cross walls – the cytoplasm is continuous throughout the individual except during the production of gametangia (Image D) – and the chloroplasts are disc shaped with 1-2 pyrenoids (Image E).
We have genetically verified records from CN to the lower reaches of the Bay of Fundy, NB. Individuals are attached to rock or invertebrates and found in low intertidal pools to subtidal (8 m).
Image A. Specimen (~5 cm tall) in a low intertidal pool on rock at Wallace Cove Lighthouse, NB (GWS045384).
Image B. Main axis percurrent and giving rise to regularly opposite branchlets, these constricted near their point of contact, in a pinnate pattern of development (low intertidal on rock at Wallace Cove Lighthouse, NB; GWS045382).
Image C. Close up of the basal attachment rhizoids, which bear the erect plumose fronds (GWS045382).
Image D. Putative gametangial production near the apices of vegetative branchlets (GWS045382).
Image E. The cytoplasm is continuous throughout the thallus; plastids are small discs with 1-2 pyrenoids (GWS045382).