Crataegus × lavalleei, sometimes known as hybrid cockspurthorn[1] or Lavallée's hawthorn, is a hybrid that arose between cultivated specimens of two species in the genus Crataegus (Hawthorn). It is an ornamental small tree with glossy dark green unlobed leaves that is used horticulturally.
The female parent was C. mexicana (sometimes mistakenly called C. pubescens), and the male parent is thought to be C. calpodendron (which is sometimes mistakenly called C. crus-galli).[2]
Carrière's hawthorn, C. × carrierei has the same parentage, and is therefore a synonym, i.e. the same species. There are minor differences between Lavallée's hawthorn and Carrière's hawthorn, and the latter is considered a separate cultivar, which is formally written as Crataegus 'Carrierei'. It has gained the Royal Horticultural Society's Award of Garden Merit.[3] The leaves turn red before falling very late in the season. This cultivar is also characterised by almost thornless stems, and abundant orange berries which last long on the tree.[3]
^Phipps, James Bird; O’Kennon, R.J.; Lance, R.W. (2003). "Chapter 7: Hawthorns". Hawthorns and medlars. Cambridge: Royal Horticultural Society. p. 102. The female parent of Crataegus x lavallei is C. mexikana and the pollen parent was suspected of being C. crus-galli, later generally repeated as fact. An unpublished M.Sc. thesis by a former student of mine, Tom Wells, provides a strong argument that C. calpodendron was the male parent. In this context it is interesting to note that C. calpodendron was in 19th-century France disguised as Mespilus fontanesiana in a number of botanic gardens and that, when it was transferred to Crataegus as C. fontanesiana, it was thought by some botanists to be a synonym of C. crus-galli.
