Colubrina greggii, commonly known as Sierra nakedwood or Gregg's colubrina, is a species of flowering plant in the family Rhamnaceae native to eastern Mexico, with a disjunct population in southern Texas in the United States.
The name honours American botanist Josiah Gregg (1806 â 1850), who collected the holotype near Monterrey, Nuevo León in 1848.
Colubrina greggii is a shrub 2âÂÂ3 m in height or a small tree, reaching 5 m. Stems zigzag and are glabrate to loosely sericeous. Leaves are alternately arranged, simple, ovate to lanceolate-ovate or elliptic-ovate, and have finely toothed margins. The blades measure 6âÂÂ18 cm in length and 3âÂÂ8 cm in width. Petioles are 4âÂÂ20 mm long. The inflorescence is a thyrse with 20-80 flowers. Peduncles measure 5âÂÂ12 mm in length. The flowers are greenish-yellow, with stamens opposite the spoon-shaped petals. Flowering takes place in the spring or summer through fall. Fruiting pedicels are 5âÂÂ10 mm in length. The fruit is a hard, globose capsule approximately 8âÂÂ10 mm in diameter, on which calyx remnants form an equatorial ring. It is very similar to C. arborescens of southern Florida and the Caribbean, and herbarium specimens of the two species are difficult to distinguish.
C. greggii can be found in the states of Coahuila, Guanajuato, Hidalgo, Nuevo León, Queretaro, San Luis Potosi, Tamaulipas, and Veracruz in Mexico. In Texas, this species is restricted to the lower Rio Grande Valley, where it is associated with Sabal mexicana at . In Queretaro and Guanajuato, C. greggii can be found in primary and secondary tropical dry forests, xeric shrublands, and oak forests from .
Colubrina greggii is part of a species complex with C. angustior of San Luis Potosi, southern Tamaulipas, and northern Veracruz and C. yucatanensis of Campeche, Quintana Roo, Yucatán, and Guatemala's Petén Department. The latter two species were considered varieties of C. greggii until they were raised to full species in 2013.