Gundelia is one of the two genera recently included in the Cichorieae according to molecular phylogenetic evidence (see Cichorieae: Systematics: circumscription of the Cichorieae) that do not have the 5-dentate ligulate flowers which are otherwise so characterstic for the tribe. Gundelia has spiny leaves as present in the tribe otherwise only in Scolymus and also its pollen is similar to Scolymus (Blackmore 1981; Robinson 1994). Moreover, both genera share the presence of both (functional) oil ducts and latex canals in the roots; functional oil ducts are very rare in the tribe and are else known only from Scorzonera and Warionia, the latter being the other genus in the tribe without ligulate 5-dentate flowers (see Cichorieae: Systematics).

The synflorescence of Gundelia is much derived and unique in the tribe, consisting of one-flowered capitula (with much reduced involucres) aggregated to secondary capitula (syncalathia), of which again a few dozens are aggregated to a second order syncalathium (Classen-Bockhoff & al. 1989). While Scolymus and Hymenonema share a chromosome number of 2n = 20, Gundelia has 2n = 18, considered as plesiomorphic in the tribe and in the Scolyminae also shared by Catananche.

Although the plants of Gundelia are conspicuous and used as vegetable, they were undercollected by botanists because of their dimensions and spiny habit and, moreover, hardly studied in more detail. Until 2009, the genus was usually treated as monospecific, with two further species considered as doubtfully distinct only. Closer studies since then have revealed that actually a considerable diversity has evolved within genus in its SW Asian distribution area and more than a dozen species were newly described. An ITS phylogeny by Hacıoglu & Fırat (2018) indicates that morphological differences such as flower number of the syncalathia correspond to the phylogenetic structure.H,I,J,K