Description: Appearing minute, as small spots on other algae 1 - 4 mm in diameter which may become united with others. Grows as a monostromatic base with erect unbranched filaments several cells long.

Habitat: Rare. Epiphytic on Fucus

Distribution: Widely distributed in the British Isles. Europe: Mediterranean, Portugal, Spain, France, Baltic Sea, Sweden and Norway. Atlantic coast of North America: Canada, New Hampshire, Massachusetts, Rhode Island, Conneticut and Long Island.

Similar Species: There are other small algae appearing as spots or stain-like patches. All difficult to identify and require microscopic examination.

Distribution Map from NBN: Chilionema reptans at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Chilionema reptans at iNaturalist World Species Observations database.

WoRMS: Chilionema reptans at World Register of Marine Species. Accepted name: Asperococcus fistulosus (Hudson) W.J.Hooker, 1833. AphiaID: 145313.

Classification: Biota; Chromista; Harosa; Heterokonta; Ochrophyta; Phaeophyceae; Fucophycidae; Ectocarpales; Chordariaceae; Chilionema