Regression analysis of the relationship between temperature at the site of origin and GC content in the 18S gene across 59 species of green algae. Temperature refers to the average temperature in the warmest month at or near the site of the species/strain’s collection. Algae from different habitats (aquatic, snow, soil) are represented with differently shaped symbols. The strain WJT24VFNP31 (Johansenicoccus eremophilus gen. et sp. nov.) is labelled. Grey line represents the fitted regression line.