The earliest Floribundas (before that name was in general use) was the Poulsen Roses, back in the early 1900’s. Poulsen was a Danish rose breeder, and his first Hybrid Tea Polyantha cross was named Red Riding Hood. A later variety was ‘Else Poulsen’ in 1924. Unfortunaltely, Poulsen doesn’t get the credit he deserved for being the first… that seems to have gone to Jackson and Perkins.
Eugene Boerhner was the “main man” there and worked exclusively on this plant from 1920 on. They were finally really introduced to great fanfare at the World’s Fair in 1939. The combination of polyanthas and hybrid teas produce a beautifully compact bush, loaded with sprays of roses. The American rose society nearly forced the name of these to be large-flowered hybrid polyanthas. Jackson and Perkins liked the more sensual name “floribunda”. I agree, it rolls off the tongue a lot better.
The name Floribunda means abundant flowers, and that is exactly what you get with a Floribunda. There are usually multiple blooms per stem, with clusters. These clusters are sometimes called sprays, so you may also here these called spray roses. They also have repeating blooming. Most are double bloom, although some are single. The types of flowers you will see can vary though.
IMO, these look at their best in a mass planting, which is why you will often see them used in Municipal gardens.
Floribunda roses have some nice traits for the garden that make them generally easy to work with. They get some winter hardiness from the hybrid tea genes. They are generally best grown in ground but can do well potted as well.