Celtis is a genus of about 60–70 species of deciduous trees, commonly known as hackberries or nettle trees, in the hemp family Cannabaceae. It has a cosmopolitan distribution.
Description
Celtis species are generally medium-sized trees, reaching tall, rarely up to tall. The leaves are alternate, simple, long, ovate-
acuminate, and evenly serrated margins. Diagnostically,
Celtis can be very similar to trees in the
Rosaceae and other rose motif families.
Small flowers of this monoecious plant appear in early spring while the leaves are still developing. Male flowers are longer and hairy. Female flowers are greenish and more rounded.
The fruit is a small drupe in diameter, edible in many species, with a dryish but sweet, sugary consistency, reminiscent of a date palm.
Taxonomy
Previously included either in the
elm family (
Ulmaceae) or a separate family, Celtidaceae, the APG III system places
Celtis in an expanded hemp family (Cannabaceae).
Phylogeny
Members of the genus are present in the fossil record as early as the
Miocene of Europe, and
Paleocene of North America and eastern Asia.
[MacPhail, M. K., N. F. Alley, E. M. Truswell and I. R. K. Sluiter (1994). "Early Tertiary vegetation: evidence from spores and pollen." History of the Australian Vegetation: Cretaceous to Recent. Ed. Robert S. Hill. Cambridge University Press. pp. 189–261. . Partially available on Google Books.][Manchester, S. R., Akhmetiev, M. A., & Kodrul, T. M. (2002). Leaves and fruits of Celtis aspera (Newberry) comb. nov. (Celtidaceae) from the Paleocene of North America and eastern Asia. International Journal of Plant Sciences, 163(5), 725-736.]
Etymology
The derivation of the name of this genus,
, is from a Latin word for an unrelated plant, the "lotus tree" of North Africa. The word was applied to this taxon by Linnaeus for unknown reasons.
Species
, the following 68 species are accepted by Plants of the World Online.
Removed from genus
-
Trema cannabina (as C. amboinensis )
-
Trema lamarckianum (as C. lamarckiana )
-
Trema orientalis (as C. guineensis or C. orientalis )
-
Trema tomentosa (as C. aspera or C. tomentosa )
Distribution and habitat
The genus is widespread throughout tropical and temperate parts of the world, occurring on all continents except Antarctica.
Ecology
Some species, including common hackberry (
C. occidentalis) and
C. brasiliensis, are honey plants and a pollen source for honeybees of lesser importance.
Lepidoptera
Celtis species are used as food plants by the
of certain
Lepidoptera. These include mainly brush-footed butterflies, most importantly the distinct genus
Libythea (beak butterflies) and some
Apaturinae (emperor butterflies):
Pathogens
The
basidiomycete fungus
Perenniporia celtis was first described from a
Celtis host plant.
Habitat Loss
Some species of
Celtis are threatened by habitat destruction.
Uses
Several species are grown as ornamental trees, valued for their drought tolerance. They are a regular feature of
arboretum and botanical gardens, particularly in North America. Chinese hackberry (
Celtis sinensis) is suited for bonsai culture; a magnificent specimen in Daegu-myeon is one of the natural monuments of South Korea.
The berries are generally edible when they ripen and fall.
Hackberry wood is sometimes used in cabinetry and woodworking.
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