What I find interesting about both the 1955 and 1958 versions is how much they were influenced by American concept cars and styling fads of the time. Not clear to me is how much Michelotti actually contributed in the way of design features. That is because the American-inspired details are largely out-of-character for him. I suspect that Nardi greatly influenced the completed designs.
Both Raggi Azzurro were on display at the Blackhawk Museum in Danville, California when I was there in March. Below are some photos I took. Their quality is hampered by the fact that the cars were jammed close to others and because the lighting in the gallery consisted of many small spotlights that are reflected by the cars' surfaces.
Lincoln Futura concept car featuring the twin-bubble canopy theme that Michelotti seems to have borrowed for the greenhouse. I have no information as to when in 1955 the Raggio was first displayed, but the Futura was announced around February (the March issue of Popular Mechanics Magazine, on news stands in February, has photos of it). So there appears to have been time for the feature to be borrowed.