Arthrochaete
Arthrochaete is a genus of green algae, in the family Chaetophoraceae, containing the sole species Arthrochaete penetrans.
Arthrochaete penetrans occurs is a multicellular alga which is easily distinguished due to its hairs, which are long and often numerous. Cells contain a large, plate-like chloroplast with one to two pyrenoids. It typically grows on or within marine algae, such as Turnerella, but it may also be epilithic. It is restricted to Arctic waters.