Hybridella globosa (Ortega) Cass. (original description)
Hymenatherum tenuifolium Cass. accepted as Thymophylla tenuifolia (Cass.) Rydb. (original description)
Hymenolepis Cass. (original description)
Hymenolepis leptocephala Cass. accepted as Hymenolepis parviflora (L.) DC. (original description)
Hymenonema fontanesii Cass. accepted as Hymenonema aspera (Desf.) DC. (original description)
Hymenonema tournefortii Cass. accepted as Hymenonema graecum (L.) DC. (original description)
Hyoseris microcephala Cass. accepted as Hyoseris scabra L. (original description)