Spongonema tomentosum (Hudson) Kützing

Description: Thallus filamentous, string-like, up to 200mm long.  Erect system of branched assimilatory filaments; branching secund, intertwining right-angled branches present. Filaments densely interwoven. Basal system of free filaments and rhizoids; some filaments aggregated into pseudodiscs.  One or two linear chloroplasts per cell.  Unilocular sporangia present; plurilocular sporangia multiseriate, elongate, terminal on short branchlets.
Habitat: Mid- to lower intertidal epiphytic on Fucus vesiculosus and Himanthalia elongata.

Species list