Achillea serrulata Hornem. accepted as Achillea ptarmica L. (original description)
Achyrophorus helveticus Hornem. (original description)
Achyrophorus hispidus Hornem. accepted as Hypochaeris cretensis (L.) Bory & Chaub. (original description)
Achyrophorus minimus Hornem. accepted as Hypochaeris arachnoides Poir. (original description)
Anthemis parthenioides Benth. ex Hornem. (original description)
Aster pusillus Hornem. (original description)
Aster speciosus Hornem. accepted as Eurybia spectabilis (Sol. ex Aiton) G.L.Nesom (original description)
Centaurea cicutifolia Hornem. (original description)
Centaurea rigescens Hornem. (original description)
Cnicus squarrosus Hornem. accepted as Cirsium squarrosum Fisch. ex Spreng. (original description)
Conyza spathulata Hornem. (original description)
Crepis coriacea Hornem. (original description)
Erigeron fastigiatus Hornem. (original description)
Gnaphalium elongatum Hornem. accepted as Helichrysum orientale (L.) Vaill. (original description)
Gnaphalium hemisphaericum Hornem. accepted as Euchiton sphaericus (Willd.) Holub (original description)
Hieracium bifidum Kit. ex Hornem. (original description)
Hieracium calcareum Bernh. ex Hornem. (original description)
Inula villosa Vahl ex Hornem. accepted as Pulicaria arabica subsp. arabica (L.) Cass. (original description)
Kuhnia frutescens Hornem. (original description)
Scorzonera stricta Hornem. (original description)
Senecio odoratus Hornem. (original description)
Sonchus hyoseridifolius Hornem. accepted as Sonchus pinnatus Aiton (original description)
Stevia stricta Hornem. (original description)
Tragopogon parviflorus Hornem. accepted as Tragopogon crocifolius subsp. crocifolius L. (original description)