The common ragweed is an annual plant with an originally Eurasian distribution which today has become almost cosmopolitan, present in all regions of Italy. It grows, often as a weed, in ruderal and segetal vegetations, on the edge of roads, in cultivated fields, orchards, gardens, landfills and forest clearings, on clay soils rich in nitrogen compounds, from sea level to the subalpine belt. The species sporadically appears on the edge of the temporary ponds of Sardinia, in contact with ruderal vegetation. The plant is toxic for the presence of alkaloids that are slow-acting, but very harmful to the liver and carcinogenic, which can also pass to honey and milk. The genus name derives from the Latin 'senex' (old), alluding to the whitish gray pappus of the fruit or to the hairiness of many species; the species name comes from the Latin 'vulgus' (common people) and it means 'common, widespread, frequent'. Flowering period: January to December.

Italian name(s): Calderaja (Italia), Calderina (Liguria, Valle d'Arroscia), Calderina (Italia), Calderugia (Toscana, Val di Chiana), Calderugia (Italia), Cardamiju (Calabria), Cardella sarvaega (Liguria, Dolceacqua), Carderina (Liguria, Valle d'Arroscia), Cardiddu (Calabria), Cardillo (Campania, Napoli, Ischia), Cardillo (Italia), Cardoncello (Toscana, Poggibonsi), Cilicione (antichi), Crescione (antichi), Erba calderina (Toscana, Scandicci), Erba calderina (Piemonte), Erba calderugia (Toscana), Erba canaja (Liguria, Chiavari, Savona), Erba canarina (Liguria, Sella), Erba cardaina (Liguria, Genova), Erba cardarena (Emilia-Romagna, Romagna), Erba cardelina (Liguria, Sarzana), Erba cardellina (Marche), Erba carderina (Toscana), Erba cardlena (Emilia-Romagna, Romagna), Erba cardlina (Emilia-Romagna, Lunigiana), Erba da canarin (Liguria, Porto Maurizio), Erba de cardaneras (Sardegna), Erba de cardeddinas (Sardegna), Erba de cardellinas (Sardegna), Erba fanetta (Liguria, Vado, Zivola), Erba gardelina (Veneto, Verona), Erba spelliciosa (Toscana), Erba uccellina (Toscana), Erba verzellina (Marche), Erbass (Piemonte, Carpeneto), Erbassun (Piemonte, Carpeneto), Erva di li cardiddi (Sicilia, Etna), Fior d'ogni mese (Veneto, Venezia), Fior d'ogni mese (antichi), Fiorone (Toscana, Pisa), Jerbe d'ogni mes (Friuli), Mangia lebbra (Sicilia, Modica), Mangia-Lebbra (Italia), Margrita (Piemonte), Mascarpin (Piemonte, Acqui), Pedrufeghe (Sardegna, Terralba), Peleciosa (antichi), Pelissun (Liguria, S. Olcese), Perdufexì (Sardegna, Terralba), Piè d'uccellino (Toscana), Sbiz (Friuli), Selissun (Liguria, Genova), Senecio volgare (Italia), Senecione (Toscana), Senecione comune (Italia), Senissun (Liguria, Valle d'Arroscia), Serbixe (Liguria, Diano, S. Remo), Sineciu (Sicilia), Smilzon (Emilia-Romagna, Bologna), Solleccione (Toscana), Sollecciosa (Toscana), Solleciola (Italia), Solliccione (Toscana), Spellicciosa (Toscana), Verzellina (Toscana), Verzellina (Italia), Zampa d'usell (Emilia-Romagna, Romagna).