Anacyclus pallescens Guss. accepted as Porophyllum ruderale subsp. macrocephalum (DC.) R.R.Johnson (original description)
Andryala cossyrensis Guss. (original description)
Andryala integrifolia Ucria & hort.panhorm.336 ex Guss. accepted as Hieracium racemosum subsp. crinitum (Sm.) Rouy (original description)
Anthemis abrotanifolia (Willd.) Guss. (original description)
Anthemis intermedia Guss. accepted as Anthemis secundiramea Biv. (original description)
Anthemis muricata (DC.) Guss. (original description)
Apargia sicula Guss. accepted as Leontodon siculus (Guss.) Nyman (original description)
Centaurea macroacantha Guss. accepted as Centaurea calcitrapa L. (original description)
Centaurea parlatoris var. tomentosa Guss. (original description)
Cnicus siculus Guss. accepted as Cnicus pungens Willd. (original description)
Crepis reflexa Guss. accepted as Crepis vesicaria subsp. hyemalis (Biv.) Babc. (original description)
Evax tenuifolia Guss. accepted as Filago pyramidata L. (original description)
Helichrysum litoreum Guss. (original description)
Helichrysum scandens Guss. accepted as Helichrysum stoechas subsp. barrelieri (Ten.) Nyman (original description)
Helichrysum stramineum Guss. accepted as Helichrysum pendulum (C.Presl) C.Presl (original description)
Hieracium siculum Guss. accepted as Hieracium symphytifolium Froel. (original description)
Hyoseris calyculata Jan ex Guss. accepted as Hyoseris radiata L. (original description)
Hypochaeris tenorii Guss. accepted as Hypochaeris radicata L. (original description)
Jasonia saxatilis (Lam.) Guss. accepted as Chiliadenus glutinosus (L.) Fourr. (original description)
Jurinea bocconi Guss. (original description)
Kentrophyllum turbinatum Gasp. ex Guss. accepted as Carthamus lanatus L. (original description)
Leontodon minimus brigant. ex Guss. accepted as Taraxacum minimum (brig. ex Guss.) N.Terracc. (original description)
Picris spinulosa Bertol. ex Guss. accepted as Picris hieracioides subsp. spinulosa (Guss.) Arcang. (original description)
Pulicaria dentata Guss. (original description)
Scorzonera decumbens (Guss.) Guss. accepted as Podospermum laciniatum subsp. decumbens (Guss.) Gemeinholzer & Greuter (original description)
Scorzonera intermedia (DC.) Guss. accepted as Podospermum laciniatum (L.) DC. (original description)
Senecio incrassatus Guss. accepted as Senecio leucanthemifolius Poir. (original description)
Senecio leucanthemifolius var. pectinatus Guss. (original description)