hawthorn, any species of the genus Crataegus of the family Rosaceae (rose family), shrubs and trees widely distributed in north temperate climates and especially common in E North America. They usually have thorns, clusters of white (rarely rose-colored) flowers in the spring, and colorful orange, red, or yellow (rarely blue or black) fruits in the fall. The fruits, called haws, resemble tiny apples; some are used in jellies. English hawthorns are of two species, C. oxyacantha and C. monogyna; the common American hawthorn, with bright red haws, is C. coccinea, called scarlet, or red, haw (as are other similar species). Hawthorns are cultivated for ornament and, especially in England, for hedges (haw also means hedge). Hawthorn wood is very hard and is used for such small items as tool handles.
In England, hawthorn flowers are associated with May Day, and the hawthorn (called also may, thorn, haw, whitethorn, and thorn apple) has long been used as a symbol of spring in English poetry. There are many legends surrounding the hawthorn, e.g., that of the Glastonbury thorn (see Glastonbury, England). A hawthorn is the state flower of Missouri. The black haw is a viburnum (see honeysuckle).
Hawthorn is classified in the division Magnoliophyta, class Magnoliopsida, order Rosales, family Rosaceae.
See study by B. Vaughn (2015).