This species forms wine-red crusts on hard substrata, typically cobble and mussel shells (Image A), although often overgrowing other algal crusts on these substrata. Crusts are composed of a hypothallus of 1-3 layers on longitudinal horizontal filaments (cells 7.5-10 µm tall by 18-46 µm long) bearing a perithallus of erect filaments to 10 cells high (typically 3-4), cells 7.5-10 µm wide by 10-14 µm tall (Image B). There is a soft layer of gel covering the surface and the filaments spread with moderate pressure. Occasionally multicellular rhizoids are produced from the hypothallus, especially when overgrowing other crustose algae (Image C). Sori include elongate paraphyses of 4-7 cells (3-5 µm wide by 7-10 µm tall; Image D), among which zonate tetrasporangia or male and female (Image E) reproductive organs are formed.
Genetically verified collections of this species were found growing from the lower mid intertidal to subtidal (10 m) on mussel shells and cobble. Uncommon, with most collections from the lower Bay of Fundy and southwestern Nova Scotia (sampling bias?), but also northern Labrador (presumably at locations in between, more sampling is necessary). We have uncovered two addition species in this relatively young genus, one from Newfoundland and the other from Haida Gwaii, BC; taxonomic work is needed.
Image A. Northern specimen on a piece of subtidal (8 m) cobble from Duck Islands, Torngat, NL (GWS040240).
Image B. Section of vegetative crust showing the vertical 1-3 layered hypothallus with a 3-4 celled perithallus (mid intertidal on mussel, Meadow Cove exposed biodiversity site, Bay of Fundy, NB; GWSC043).
Image C. Multicellular rhizoid (arrow) formed from a basal hypothallus cell of a crust overgrowing another red algal crustose species of Hildenbrandia (GWSC043).
Image D. Paraphyses of the adventitious nemathecium in a female specimen (subtidal (6 m) on cobble, N Head of Evans Bight, Torngat, Labrador, NL; GWS040293).
Image E. Carpogonium (arrow) terminating a carpogonial branch among the nemathecial paraphyses (GWS040293).