This red alga consists of solid stipes bearing hollow rounded to flattened axes, these simple to sparingly (Image A) or proliferously (Images B, C) branched. In transverse section younger axes are hollow with two to three layers of large colorless cells subtending an outer one to two layers of pigmented cortical cells (Image D). At times confused with Dumontia contorta (Gmelin) Ruprecht and Cystoclonium purpureum (Hudson) Batters, D. ramentacea is distinct in lacking any filamentous construction in the medulla (Image D).
We have genetically verified collections from southern ME in the south, to Churchill, MB, in the west and central Baffin Island, NU, in the north. Plants grow gregariously from mid intertidal pools, through the low intertidal zone, thinning to subtidal individuals at 10 m, typically on rock, at a wide range of semi-sheltered to exposed locations. This species can be highly variable in morphology, some of which is recorded in the BOLD taxonomy browser.
Image A. Sparingly branched individuals (low intertidal on rock; Letete exposed biodiversity site, Bay of Fundy, NB, 22.3.2007; GWS005931).
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Image B. More proliferously branched individuals (low intertidal on rock; Wallace Cove Lighthouse, NB, 1.5.2013; GWS034080).
Image C. Proliferously branched individuals (subtidal (4 m) on rock; Gaulman Pt., NS, 15.8.2012; GWS032144).
Image D. Transverse vegetative section showing the pseudoparenchymatous medulla and hollow center (mid intertidal pool on rock; Lepreau exposed biodiversity site, Bay of Fundy, NB, 7.5.2015; G1002).
Seaweed of Canada 