Agoseris glauca var. parviflora (Nutt.) Rydb. accepted as Agoseris parviflora (Nutt.) D.Dietr. (original description)
Aster multiflorus var. incanopilosus (Lindl.) Rydb. accepted as Symphyotrichum falcatum var. commutatum (Torr. & A.Gray) G.L.Nesom (original description)
Carduus drummondii Rydb. (original description)
Carduus plattensis Rydb. (original description)
Carduus plattensis var. spinosior Rydb. (original description)
Carduus undulatus var. ochrocentrus (A.Gray) Rydb. accepted as Cirsium undulatum (Nutt.) Spreng. (original description)
Crepis barbigera Leiberg ex Coville (original description)
Crepis barbigera Leiberg (original description)
Crepis monticola Coville (original description)
Crepis rostrata Coville accepted as Crepis modocensis subsp. rostrata (Coville) Babc. & Stebbins (original description)
Crepis scopulorum Coville accepted as Crepis modocensis subsp. modocensis Greene (original description)
Crepis subacaulis (Kellogg) Coville accepted as Crepis modocensis subsp. subacaulis (Kellogg) Babc. & Stebbins (original description)
Ptilepida grandiflora (Torr. & A.Gray) Rose accepted as Hymenoxys grandiflora (Torr. & A.Gray ex Torr. & A.Gray) K.F.Parker (original description)
Solidago canadensis var. gilvocanescens Rydb. accepted as Solidago altissima subsp. gilvocanescens (Rydb.) Semple (original description)
Solidago missouriensis var. glaberrima (M.Martens) Rydb. (original description)
Thurovia Rose (original description)
Thurovia triflora Rose (original description)
Tridax tenuifolia Rose (original description)
Tridax tenuifolia var. microcephala Rose (original description)