• ×Anthematricaria dominii Rohlena
• ×Anthemimatricaria inolens P.Fourn.
• ×Anthemimatricaria maleolens P.Fourn.
• ×Anthemimatricaria sulfurea P.Fourn.
• ×Argyrautia degeneri Sherff
• ×Asterigeron ucrainicus Tzvelev (uncertain > unassessed)
• ×Carduogalactites ludoviciae (Bertr.) P.Fourn.
• ×Chrysaboltonia pulcherrima Arends (uncertain > unassessed)
• ×Chrysanthemoachillea borzae Prodan (uncertain > unassessed)
• ×Chrysanthemoachillea carmen-sylvae Prodan ex Nyár. (uncertain > unassessed)
• ×Cirsio-carduus borderi (Rouy) Arènes (uncertain > unassessed)
• ×Cirsio-carduus cirsiformis (Vuk.) Arènes
• ×Cirsio-carduus hohenackeri Arènes
• ×Cirsio-carduus jaubertianus (Sennen & Septimin) Arènes
• ×Cirsio-carduus lutetianus Arènes
• ×Cirsio-carduus parisiensis P.Fourn.
• ×Crepi-Hieracium garnieri (Petitm.) P.Fourn.
• ×Filfia mixta (Holuby) Holub
• ×Heterokalimeris maruyamae Kitam. (uncertain > unassessed)
• ×Raymondiella weatherbiana (Fernald) B.Boivin accepted as Cyperus ×weatherbianus Fernald
• ×Solidaster hybridus Wehrhahn (uncertain > unassessed)
• ×Solidaster lutens M.L.Green
• ×Solidaster luteus (Everett) M.L.Green (uncertain > unassessed)
• ×Solidaster luteus (Everett) M.L.Green ex Dress
• Aaronsohnia factorovskyi Warb. & Eig accepted as Otoglyphis factorovskyi (Warb. & Eig) Oberpr. & Vogt
• Aaronsohnia pubescens (Desf.) K.Bremer & Humphries accepted as Otoglyphis pubescens (Desf.) Pomel
• Aaronsohnia pubescens subsp. maroccana (Ball) Fennane & Ibn Tattou
• Aaronsohnia pubescens subsp. pubescens (Desf.) K.Bremer & Humphries
• Abacella cornuta Shuysky, 1973 †
• Abacella delicatula J.H.Johnson, 1964 †
• Abacella dentata Shuysky, 1973 †
• Abacella pertusa Maslov, 1956 †
• Abacella pustulata Shuysky, 1973 †
• Abacella stellata Shuysky, 1991 †
• Abies alba Mill.
• Abildgaardia chinensis Gand. (uncertain > unassessed)
• Abildgaardia fusiformis (Wangwasit & D.A.Simpson) Larridon
• Abildgaardia geminata Schrad. ex Nees (uncertain > unassessed)
• Abildgaardia laevigata Willd. ex Steud. (uncertain > unassessed)
• Abildgaardia longistipitata (Tang & F. T. Wang) B. Z. Li & S. R. Zhang
• Abildgaardia macrantha (Boeckeler) Goetgh.
• Abildgaardia metalliphila Lye (uncertain > unassessed)
• Abildgaardia mexicana (Palla) Kral
• Abildgaardia natalensis Gand. (uncertain > unassessed)
• Abildgaardia odontocarpa (S.T.Blake) K.L.Wilson & J.J.Bruhl
• Abildgaardia ovata (Burm.f.) Kral
• Abildgaardia oxystachya (F.Muell.) K.L.Wilson & J.J.Bruhl
• Abildgaardia pachyptera (S.T.Blake) K.L.Wilson & J.J.Bruhl
• Abildgaardia papillosa Kral & M.T.Strong (uncertain > unassessed)
• Abildgaardia polygama Spreng. (uncertain > unassessed)
• Abildgaardia schoenoides R.Br.
• Abildgaardia ternata Schrad. ex Nees (uncertain > unassessed)
• Abildgaardia triflora (L.) Abeyw.
• Abrotanella caespitosa Petrie ex Kirk
• Abrotanella diemii Cabrera
• Abrotanella emarginata (Gaudich.) Cass.
• Abrotanella fertilis Swenson
• Abrotanella forsterioides (Hook.f.) Benth. (uncertain > unassessed)
• Abrotanella forsteroides (Hook.f.) Benth. (uncertain > unassessed)
• Abrotanella inconspicua Hook.f.
• Abrotanella linearifolia A.Gray
• Abrotanella linearis Berggr.
• Abrotanella muscosa Kirk
• Abrotanella nivigena (F.Muell.) F.Muell. (uncertain > unassessed)
• Abrotanella nivigena (F.Muell.) F.Muell. ex Benth.
• Abrotanella patearoa Heads
• Abrotanella purpurea Swenson
• Abrotanella pusilla (Hook.f.) Hook.f.
• Abrotanella rostrata Swenson
• Abrotanella rosulata (Hook.f.) Hook.f.
• Abrotanella scapigera (F.Muell.) F.Muell. ex Benth. (uncertain > unassessed)
• Abrotanella spathulata (Hook.f.) Hook.f.
• Abrotanella submarginata A.Gray
• Abrotanella trichoachaenia Cabrera
• Abrotanella trilobata Swenson
• Abutilon theophrasti Medik.
• Acalypha wilkesiana Müll. Arg.
• Acamptopappus shockleyi A.Gray
• Acamptopappus sphaerocephalus (Harv. & A.Gray) A.Gray
• Acamptopappus sphaerocephalus var. hirtellus S.F.Blake
• Acamptopappus sphaerocephalus var. sphaerocephalus (Harv. & A.Gray ex A.Gray) A.Gray
• Acanthocephalus amplexifolius Kar. & Kir.
• Acanthocephalus benthamianus Regel
• Acanthocereus tetragonus (Linnaeus) Hummelinck, 1938
• Acanthocladium dockeri F.Muell.
• Acanthococcus anglicus A.W.Bennett, 1888 accepted as Glochiococcus anglicus (A.W.Bennett) De Toni, 1888
• Acanthodesmos distichus C.D.Adams & duQuesnay
• Acanthodesmos gibarensis P.Herrera & P.A.González (uncertain > unassessed)
• Acanthospermum australe (Loefl.) Kuntze
• Acanthospermum consobrinum S.F.Blake
• Acanthospermum glabratum (DC.) Wild
• Acanthospermum hispidum DC.
• Acanthospermum humile (Sw.) DC.
• Acanthospermum microcarpum B.L.Rob.
• Acanthosphaera zachariasii Lemmermann, 1899
• Acanthostyles buniifolius (Hook. & Arn.) R.M.King & H.Rob.
• Acanthostyles saucechicoensis (Hieron.) R.M.King & H.Rob.
• Acanthus ebracteatus Vahl
• Acanthus ebracteatus subsp. ebarbatus R.M.Barker
• Acanthus ebracteatus subsp. ebracteatus Vahl