What is "haplopappus"

Haplopappus is a genus of flowering plants in the aster family.

Many species once included in Haplopappus are now regarded as belonging to other genera: Acamptopappus Ageratina Aztecaster Benitoa Croptilon Ericameria Grindelia Gundlachia Haploësthes Hazardia Inulopsis Isocoma Leptostelma Llerasia Lorandersonia Machaeranthera Nestotus Noticastrum Oonopsis Oreochrysum Oreostemma Osbertia Pyrrocoma Rayjacksonia Stenotus Toiyabea Tonestus Xanthisma