(also known as "weeds")
I looked and the yellow flowers on the long stalks are definitely the flowers belonging to the little trifoliate shrubby things. But I noticed that both the flowers and the leaves fold up at night, which is the same thing that wood sorrel does. Wood sorrel also has trifoliate leaf groupings with big flowers (though white and not on stalks) so maybe it isn't a type of clover.
Checked in both English language and Italian bookshops today for a Wildflowers of Italy book but no go.
I see that wood sorrel does have leaves that look a lot more like our little Italian mystery plant than clover.
and I see that the flowers are indeed on stalks.
So, I bet it's an Oxalis, not a Trifolium after all.
Oxalis arborea, looks almost exactly like it, only white, including the flower clusters on long stalks.