Bernardia is a genus of flowering plants in the family Euphorbiaceae, placed within the order Malpighiales. The genus was first described for science in 1754 and comprises approximately 70 species distributed across the Americas, from the southwestern and south-central United States through Mexico, the West Indies, Central America, and South America.
Members of the genus are typically shrubs, herbs, or subshrubs and are dioecious (occasionally monoecious), meaning male and female flowers are borne on separate individuals. The plants lack latex, a feature that distinguishes them from many other euphorbs. Leaves are persistent, alternate, and simple, with stipules that may be persistent or early-falling. Leaf blades are unlobed with coarsely crenate to serrate margins, and the venation is pinnate with strong secondary veins ascending from the base. The indumentum is characteristically stellate (star-shaped) in most species.
Flowers are small and lack petals. Staminate flowers are arranged in spicate thyrses in the leaf axils; pistillate flowers are solitary. Fruits are capsules bearing subglobose seeds that lack a caruncle; the base chromosome number is x = 13. North American species of Bernardia are distinctive within the genus in being rounded shrubs with relatively small leaves and stellate vestiture, as opposed to the predominantly herbaceous or subshrubby habit of most tropical species.
Distribution
Bernardia is native to the southwestern and south-central United States, Mexico, the West Indies, Central America, and South America. The genus reaches its northern limit in the arid and semi-arid regions of Texas, New Mexico, and Arizona, where a handful of shrubby species grow in desert scrub and dry limestone slopes.
Taxonomy Notes
The genus was first described in 1754 and belongs to the family Euphorbiaceae, order Malpighiales. Several species formerly placed in Bernardia have since been transferred to related genera including Adelia, Adenophaedra, Garciadelia, Lasiocroton, and Tetracoccus (the last now placed in the segregate family Picrodendraceae).
