In May the portuguese mountains are covered in yellow.... the plant is called
Cytisus striatus is a species of flowering plant in the legume family known by the
common name Portuguese broom. This plant is native to the Iberian Peninsula but it
is also known in other parts of the world as an introduced species. It was introduced
to California in the 1960s to be used as an erosion-controlling groundcover, but
it spread and is now a noxious weed there

In Portugal the common name is - Giesta - but it is also known as May flower and in the
Northern villages it is supposed to keep satan away so people put them in their doorways,
on the 1st of May.