Gladiolus species have their original habitat in South Africa and in the southern part of Europe. Of approximately 200 species, only 12 are known to have contributed to the development of our modern, summer-flowering varieties.
In past years most of the varieties grown were classified according to three main types as follows: grandiflorus type, which produces large, showy flowers with strong spikes and many florets open at the same time; primulinus type, which produces slender, graceful spikes and hooded florets; primulinus grandiflorus, which has the composite characteristics of the other two types. Within recent years, however, hybridizers have so thoroughly mixed gladiolus stocks that few varieties can be classified according to type.
Grove, L. C.
"Growing the Gladiolus,"
Bulletin P: Vol. 3
, Article 1.
Available at: http://lib.dr.iastate.edu/bulletinp/vol3/iss85/1