Crataegus × mordenensis, Morden Hawthorn, is a hybrid that arose between two species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 in the genus Crataegus

Crataegus

Crataegus , commonly called hawthorn or thornapple, is a large genus of shrubs and trees in the rose family, Rosaceae, native to temperate regions of the Northern Hemisphere in Europe, Asia and North America. The name hawthorn was originally applied to the species native to northern Europe,...

(Hawthorn), Crataegus laevigata and Crataegus succulenta

Crataegus succulenta

Crataegus succulenta is a species of hawthorn known by the common names fleshy hawthorn and succulent hawthorn. It is "the most wide-ranging hawthorn in North America", native to much of southern Canada, and the United States as far south as Arizona, New Mexico, Kansas, Missouri, North Carolina,...

. This hybrid was first raised at the Agriculture Canada Plant Breeding Station in Morden, Manitoba, in 1935.

Two cultivar

Cultivar

A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...

s of this hybrid are significant in horticulture: 'Toba', with white double flowers that age to pink, and 'Snowbird' with white double flowers.