This species with a wide Eurasian distribution is present in all regions of Italy; the nominal subspecies is found in north-central Italy except in Piedmont, Tuscany and Lazio. It grows in marshy reed vegetation along the banks of canals and ponds, or in wet meadows, on silty-clayey to peaty, sometimes flooded soils which are rich in bases and nitrogen compounds, from sea level to the montane belt. The species is common in the central and intermediate belts of the Sardinian temporary ponds. The genus name derives from the Greek 'gala' (milk), which is also related to the Italian 'caglio' (rennet): different species were used to curdle milk in cheese-making; the species name refers to the habitat. Flowering period: May to July.

Italian name(s): Caglio delle paludi (Italia), Caglio palustre (Italia), Galium palustre (Italia), Ruggia (Sicilia, Etna), Stellina ruvida (Toscana, Val di Chiana).