Obligate epiphyte on Odonthalia and Rhodomela, depending on location: see habitat page (Lamb).  No research is currently looking at other interactions of this species.  One observation in the field was the presence of small egg cases that had been laid on the thalli of Soranthera.  These egg cases were also present on the host plant and other low intertidal algae such as Fucus spp..  The presence of these eggs suggests the possibility of this alga possessing other interactions with organisms in the surrounding habitat.

Picture: Soranthera observed growing on Odonthalia at Rueben Tarte Park, San Juan Island, Washington

Lamb, Andy, Hanby, Bernard P.. Marine Life of the Pacific Northwest. Harbour Publishing.