Carduus afromontanus R.E.Fr. (original description)
Carduus centifolius R.E.Fr. accepted as Carduus millefolius R.E.Fr. (original description)
Carduus conjungens R.E.Fr. (original description)
Carduus ellenbeckii R.E.Fr. accepted as Carduus schimperi subsp. schimperi Sch.Bip. (original description)
Carduus keniensis R.E.Fr. (original description)
Carduus kikuyorum R.E.Fr. accepted as Carduus nyassanus subsp. kikuyorum (R.E.Fr.) C.Jeffrey (original description)
Carduus kilimandscharicus R.E.Fr. accepted as Carduus keniensis R.E.Fr. (original description)
Carduus millefolius R.E.Fr. (original description)
Carduus nanus R.E.Fr. accepted as Carduus schimperi subsp. nanus (R.E.Fr.) C.Jeffrey (original description)
Carduus nyassanus (S.Moore) R.E.Fr. (original description)
Carduus platyphyllus R.E.Fr. accepted as Carduus schimperi subsp. platyphyllus (R.E.Fr.) C.Jeffrey (original description)
Carduus silvarum R.E.Fr. (original description)
Carduus steudneri (Engl.) R.E.Fr. accepted as Carduus nyassanus subsp. kikuyorum (R.E.Fr.) C.Jeffrey (original description)
Carduus stolzii R.E.Fr. accepted as Carduus leptacanthus Fresen. (original description)
Carduus subalpinus R.E.Fr. accepted as Carduus keniensis R.E.Fr. (original description)
Carduus theodori R.E.Fr. accepted as Carduus schimperi subsp. schimperi Sch.Bip. (original description)
Echinops aberdaricus R.E.Fr. (original description)
Echinops luckii R.E.Fr. accepted as Echinops longifolius A.Rich. (original description)
Sonchus afromontanus R.E.Fr. (original description)
Sonchus ledermannii R.E.Fr. accepted as Lactuca lasiorhiza (O.Hoffm.) C.Jeffrey (original description)
Sonchus obtusilobus R.E.Fr. (original description)
Sonchus pycnocephalus R.E.Fr. accepted as Launaea rogersii (Humbert) Humbert & Boulos (original description)
Sonchus rueppellii (Sch.Bip. ex Oliv. & Hiern) R.E.Fr. accepted as Launaea rueppellii (Sch.Bip. ex Oliv. & Hiern) Amin ex Boulos (original description)
Sonchus stenophyllus R.E.Fr. (original description)
Sonchus verdickii (De Wild.) R.E.Fr. accepted as Launaea verdickii (De Wild.) Boulos (original description)
Sonchus wilmsii R.E.Fr. (original description)
Tolpis ephemera (Hiern) R.E.Fr. accepted as Tolpis capensis (L.) Sch.Bip. (original description)
Tolpis somalensis R.E.Fr. accepted as Erythroseris somalensis (R.E.Fr.) N.Kilian & Gemeinholzer (original description)