Ixeris monocephala Cass. accepted as Agoseris coronopifolia (d'Urv.) K.L.Chambers (original description)
Paleya Cass. accepted as Crepis L. (original description)
Paleya albida (Vill.) Cass. accepted as Crepis albida Vill. (original description)
Petalolepis Cass. accepted as Ozothamnus R.Br. (original description)
Petalolepis ferruginea Cass. (original description)
Petalolepis rosmarinifolia Cass. (original description)
Petrobium forsteri Cass. (original description)
Phaecasium Cass. accepted as Crepis L. (original description)
Phaecasium lampsanoides Cass. accepted as Crepis pulchra L. (original description)
Phaenixopus Cass. accepted as Lactuca L. (original description)
Phaenixopus decurrens Cass. accepted as Lactuca viminea (L.) J.Presl & C.Presl (original description)
Phaenixopus ramosissimus (All.) Cass. accepted as Lactuca viminea subsp. ramosissima (All.) Arcang. (original description)
Phagnalon spathulatum Cass. accepted as Phagnalon rupestre (L.) DC. (original description)
Phagnalon subdentatum Cass. (original description)
Phagnalon tricephalum Cass. accepted as Phagnalon sordidum (L.) Rchb. (original description)
Phalacroloma Cass. accepted as Erigeron L. (original description)
Phalacroloma acutifolium Cass. (original description)
Phalacroloma obtusifolium Cass. (original description)
Philostizus Cass. accepted as Centaurea L. (original description)
Philostizus fontanesianus Cass. (original description)