3. Celtis Linnaeus, Sp. Pl. 2: 1043. 1753; Gen. Pl. ed. 5, 467, 1754.
Hackberry, sugarberry, bois inconnu [Classical Latin, Pliny's name for Celtis australis Linnaeus, the "lotus" of the ancient world]
Trees or rarely shrubs , to 30 m; crowns spreading. Bark usually gray, smooth or often fissured and conspicuously warty. Branches without or with thorns, slender, glabrous or pubescent. Leaves: stipules falling early. Leaf blade deltate to ovate to oblong-lanceolate, base oblique or cuneate to rounded, margins entire or serrate-dentate; venation 3(-5)-pinnate. Inflorescences: staminate inflorescences cymes or fascicles; pistillate solitary or few-flowered clusters. Flowers usually unisexual, staminate and pistillate on same plants, along with a few bisexual flowers, pedicellate on branches of current year, appearing in mid or late spring. Staminate flowers: filaments incurved in bud, exserted after anthesis; gynoecium minute, rudimentary. Pistillate flowers: calyx slightly to deeply 4(-5)-lobed; stamens 4-5, inserted on pilose receptacle, included, often nonfunctional filaments usually shorter than in staminate flowers, rarely absent; anthers ovate, face to face in bud, extrorse; ovaries sessile, ovoid, 1-locular; styles short, sessile, divided into 2 divergent, elongate, reflexed lobes, lobes entire or 2-cleft. Fruits fleshy drupes, ovoid or globose; outer mesocarp thick, firm, inner mesocarp thin, fleshy; stones thick walled, ripening in autumn, persisting after leaves fall. x = 10.
Species ca. 60 (6 in the flora): tropical and temperate regions, worldwide.
The hackberries provide important wildlife habitat, forming thickets that give shelter and fleshy drupes that ripen in autumn, persist after leaves fall, and supply winter food for birds and mammals. The treatment presented here is a simplified circumscription of species with no elaboration of infraspecific variation or interspecific hybridization. The group is taxonomically complex and in need of revision.
Correll, D. S. and M. C. Johnston. 1970. Manual of the Vascular Plants of Texas. Renner, Tex.