Celtis is a genus of deciduous trees belonging to the Cannabaceae family that contains 60 to 70 species. Many species of Celtis are highly valued as ornamental trees and can thus be found in botanical gardens throughout North America, while other species face the possibility of extinction due to loss of habitat. These medium-sized trees can be found all around the temperate regions of the northern hemisphere. They bear small drupes as fruit, and the trees themselves are generally eaten by caterpillars of the Lepidoptera order.
One species, Celtis occidentalis, or hackberry, is a large tree that grows from 40 to 60 feet (12 to 18 m). It has leaves very similar to the elm tree, and one can identify the hackberry by the distinct warts and ridges on the bark. During the summer, this tree produces drupe fruit; some examples of drupes are olives and mangos. In North America, the tree is very popular as a subtle accent or shade tree due to its full and graceful crown, ability to survive extreme weather conditions, and its fruit, which attracts many animals.
Celtis tenuifolia, or the dwarf hackberry, is native to the eastern states of the United States. This species is frequently mistaken for the more common Celtis occidentalis, but it can be easily identified if one knows what to look for. For example, the warts or bumps on the common hackberry’s trunk are never present on the dwarf hackberry. The dwarf hackberry also prefers very dense growth, while the other specie thrives best in open spaces. This species is wind-pollinated, and the fruits are spread about by small birds and the occasional mammal.
A commonly cultivated species, the Celtis reticulata, also known as the Texas sugarberry, palo blanco, and netleaf hackberry, is much smaller than most species belonging to this genus. It is an important tree for both birds and certain species of moth. The birds eat the drupe fruit of the tree, and moth caterpillars feast on its leaves.
Celtis luzonica is a species that is native to the Philippines, but as of 2010, it is classified as vulnerable due to habitat loss. The rapid decline in its numbers are owing to the country’s shifting cultivation and logging industry. Some effort has been made to monitor the species’ reproduction, and Philippines researchers have taken an interest in finding treatments for antibiotic-resistant fungi that can afflict the species.