Description: Microscopic filaments with branches growing endophytically.

Habitat: Rare. Endophytic in the cell walls of Cladophora or Chaetomorpha. Littoral or sublittoral.

Distribution: British Isles, but no recent records. Europe: the Mediterranean, Spain, France, Baltic Sea, Norway, Faroes and Iceland. Greenland. Atlantic coast of North America: Canada, New Hampshire and Massachusetts.

Similar Species: Required microscopic examination for identification.

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

iNaturalist: Entocladia leptochaete at iNaturalist World Species Observations database.

WoRMS: Entocladia leptochaete at World Register of Marine Species. Accepted name: Ulvella leptochaete (Huber) R.Nielsen, C.J.O'Kelly & B.Wysor, 2013. AphiaID: 732246.

Classification: Biota; Plantae; Viridiplantae; Chlorophyta; Chlorophytina; Ulvophyceae; Ulvales; Ulvellaceae; Entocladia