cardus
Could not find carduum in Logeion dictionaries.
carduum Noun: masculine genitive plural of cardus
cardŭs, ūs, m. Capit. Pert. 12, 2 ; Diocl. 6, 1, et cardŭus, ī, m. , chardon : Virg. G. 1, 151 || cardon : Plin. 19, 54.
Invenientes campulum plenum Cardis, etc.Pluries ibi. Vide supra Cardi.
cardus, ūs, m.: cardo e carciofo.