Romanesco, also known as Romanesque cauliflower or Romanesco broccoli, is an edible flower bud of the species Brassica oleracea. First documented in Italy, it is light green in color. Romanesco has a striking appearance because its form is a natural approximation of a fractal. When compared to a traditional cauliflower, as a vegetable its texture is far more crunchy, and its flavour is not as assertive, being delicate and nutty.
Romanesco was first documented in Italy (as broccolo romanesco). It is sometimes called broccoflower, but that name has also been applied to green cauliflower cultivars.
Romanesco superficially resembles a cauliflower, but it is light green in colour, and its form is strikingly fractal in nature. The inflorescence (the bud) is self-similar in character, with the branched meristems making up a logarithmic spiral. In this sense the bud’s form approximates a natural fractal; each bud is composed of a series of smaller buds, all arranged in yet another logarithmic spiral. This self-similar pattern continues at several smaller levels. The pattern is only an approximate fractal since the pattern eventually terminates when the feature size becomes sufficiently small. The number of spirals on the head of Romanesco broccoli is a Fibonacci number.
As a vegetable Romanesco is rich in vitamin C, vitamin K, dietary fiber and carotenoids.
The causes of its differences in appearance from the normal cauliflower and broccoli have been modeled as an extension of the preinfloresence stage of bud growth, but the genetic basis of this is not known.