Description: Filaments grow endophytically within Gracilaria bursa-pastoris, emerging as erect microscopic tufts.

Habitat: Rare. Endophytic in Gracilaria bursa-pastoris.

Distribution: Apparently found only on the south coast of England and north France.

Similar Species: Petrospongium berkeleyi (Gravelle) Nägeli ex Kützing.

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

iNaturalist: Cylindrocarpus microscopicus at iNaturalist World Species Observations database.

GBIF data for Cylindrocarpus microscopicus

WoRMS: Cylindrocarpus microscopicus at World Register of Marine Species. Accepted name: Cylindrocarpus microscopicus P.L.Crouan & H.M.Crouan, 1851. AphiaID: 144952.

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