Gymnanthemum congestum Cass. accepted as Eremosis triflosculosa (Kunth) Gleason (original description)
Gymnanthemum cupulare Cass. accepted as Gymnanthemum coloratum (Willd.) H.Rob. & B.Kahn (original description)
Gymnanthemum fimbrilliferum (DC.) Cass. (original description)
Gymnocline Cass. accepted as Tanacetum L. (original description)
Gymnocline leucocephala Cass. accepted as Tanacetum macrophyllum (Waldst. & Kit.) Sch.Bip. (original description)
Gymnocline vaillantii Cass. accepted as Tanacetum achilleifolium (M.Bieb.) Sch.Bip. (original description)
Gymnocline xanthocephala Cass. accepted as Tanacetum achilleifolium (M.Bieb.) Sch.Bip. (original description)
Gyptis commersonii Cass. (original description)
Gyptis pinnatifida Cass. accepted as Gyptis tanacetifolia (Gillies ex Hook. & Arn.) D.J.N.Hind & Flann (original description)
Hamulium alatum (L.) Cass. (original description)
Harpalium rigidum Cass. accepted as Helianthus pauciflorus Nutt. (original description)
Hedypnois tournefortii Cass. accepted as Hedypnois rhagadioloides (L.) F.W.Schmidt (original description)
Helianthus platycephalus Cass. accepted as Helianthus annuus L. (original description)
Helianthus polycephalus Cass. (original description)
Helichrysum dubium Cass. (original description)