Ehretia anacua is medium-sized tree found in eastern Mexico and southern Texas in the United States. It is a member of the borage family, Boraginaceae. One of its common names, anacua, is derived from the Mexican Spanish word anacahuite, as is that of the related Cordia boissieri, the anacahuita.[1] That word in turn is derived from the Nahuatl words āmatl, meaning "paper," and cuahuitl, meaning "tree,"[2] possibly referring to the bark. It is also known as knockaway, a corruption of anacua, and sandpaper tree.[1] Alternate spellings are anaqua and anachua.[3]
Anacua reaches a height of 20-[1] and a diameter of 0.3m (01feet),[4] often producing suckers or multiple trunks.[1] The bark is reddish-brown to gray with narrow furrows and peeling scales. The dark green leaves are 3- and 2- wide and elliptical or ovate. Their upper surfaces are remarkably rough, feeling like low-grade sandpaper.[4] Anacua is a partial evergreen, replacing some of the leaves in early spring. Abundant white flowers[1] form in panicles or cymes[5] 5- in length at the ends of twigs,[4] making trees appear to be covered in snow when in bloom from spring to summer.[1] Flowers are 8mm wide and have 5 corolla lobes. The fruits are spherical[4] drupes[6] 8 mm in diameter and yellowish-orange.[4] The drupes contain two stones, each with two seeds.[4] In addition to being edible by humans, the drupes are eaten by mammals and birds[1] such as the clay-colored thrush.[7] The lifespan of an Anacua is at least 50 years.[8]
Anacua is found on dry hillsides as a shrub, but reaches tree size in the moist soils of riparian zones and floodplains. It can be found at elevations from sea level to 1000feet.[4]
The leaves of E. anacua are the sole food source of the Texas tortoise beetle (Coptocycla texana).[9]