pirsonia pirsonia pirsonia is a non photosynthetic genus of heterokonts. it comprises the entirety of the family pirsoniaceae, order pirsoniida and class pirsonea in the subphylum bigyromonada, phylum gyrista. pirsonia scientific classification domain: eukaryota clade: diaphoretickes clade: sar clade: stramenopiles phylum: gyrista class: pirsoneacavalier-smith 2017 order: pirsoniidacavalier-smith & chao 2006 family: pirsoniaceaecavalier-smith 1998 genus: pirsoniaschnepf, debres & elbrachter 1990 species p. diadema p. eucampiae p. formosa p. guinardie p. mucosa p. punctigerae p. verrucosa taxonomy class pirsonea cavalier-smith 2017 order pirsoniales cavalier-smith 1998 family pirsoniaceae cavalier-smith 1998 pirsonia schnepf, debres & elbrachter 1990 p. diadema kühn 1996 p. eucampiae kühn 1996 p. formosa kühn 1996 p. guinardie schnepf, debres & elbrachter 1990 p. mucosa kühn 1996 p. punctigerae p. verrucosa kühn 1996