Authored by: Dr. Kim D. Coder Let’s play a tree game. How many of Georgia’s native trees can you identify? There are more than 260 native trees from the mountains to the sea in Georgia. The second-most numerous genera group among Georgia’s native trees is Crataegus—hawthorns. How many hawthorns can you find and identify? They are all over the place! They surround us in dense forests and open woodlands—on bottomlands, ridgetops and rocky slopes. Most people only know hawthorns from mayhaw jelly, and from an occasional “thorn” bush along the edge of a trail. Hawthorns (Crataegus spp.) are small trees or shrubs, usually with straight sharp thorns, in the rose family (Rosaceae) of plants. It has beautiful flowers and small round apple-like fruit. This genus is large and complex making identification difficult. Most people use the generic term “hawthorn” for any of the genus members, and seldom try to identify trees to species level. Hawthorns come in many tree forms greater than 12 feet tall, and equally as many smaller shrub forms. Common names for generic Crataegus species include hawthorn, haw, red haw, she-haw, thorn, thorn-apple, hog-apple, quickthorn, May-tree, white-thorn, chastity tree, and hawberry. With so many species, local common names abound and a number of species have the same common name, leading to identification confusion. There are 37 tree-forms of native hawthorns in Georgia. Of these, there are 29 different species and 8 hybrids of existing species. One hawthorn species is found only in Georgia, and five native hawthorns are found in Georgia and 1-2 other southern states. Eight of our native hawthorn species in Georgia are shared across more than 20 other states. Crataegus is a huge genus with many named species and varieties. Before 1895, only ~20 species were recognized in North America. Between 1895 and 1915, three authors described 1,500 different species in North America. One author alone named more than 1,000 species based upon minor visual differences. Today, Crataegus is considered to have about 150 species across the Northern Hemisphere, with ~90 in North America and ~60 in Eurasia. Crataegus species found in eastern North America range from Newfoundland to Florida. The genus Crataegus is currently cited having ~50-60 species in the southeastern United States. Many general tree references lump all hawthorns into a genus group and do not attempt individual species identification other than for a few common, widespread species. Crataegus species taxonomy and field identification are notorious for their difficulty, in part due to original species concepts based upon minor morphology differences. The Crataegus genus has many traditional species, as well as many asexually reproducing species (agamospecies). The interactions among all these species and their overlap in ranges has led to confusion in species identification. The Warnell Outreach website publication cited below provides a checklist and further information for the small native trees in Crataegus. Native Hawthorn (Crataegus) Tree Forms of Georgia: An Introduction To The Genus & Field Checklist. Warnell School of Forestry & Natural Resources Outreach Publication WSFNR22-32A. Pp.25. You may not see them, but hawthorns surround us hidden in open woodlands, on mountain sides, and beside coastal plain bay heads. Hawthorns represent many individual species, but usually go unnoticed as a group. If noticed at all, they are frequently lumped together into a single taxonomic unit. These small trees are worth understanding and appreciating for their values and uniqueness in Georgia woodlands. How many can you find and identify in the field? Do not be a large tree snob—can you find five hawthorns—can you find two?
