Mahonia


Mahonia is a genus of approximately 70 species of evergreen shrubs and rarely small trees in the family Berberidaceae, native to eastern Asia, the Himalaya, North and Central America. They are closely related to the genus Berberis and botanists disagree on whether to recognize a separate Mahonia. Many botanists prefer to classify Mahonia as a part of Berberis because several species in both genera are able to hybridize, and because there are no consistent morphological differences between the two groups other than the leaf pinnation. However, a recent DNA-based phylogenetic study retains the two separate genera, by clarifying that unifoliolate-leaved Berberis s.s. is derived from within a paraphyletic group of shrubs bearing imparipinnate evergreen leaves, which the paper then divides into three genera: Mahonia, Alloberberis, and Moranothamnus ; it confirms that a broadly-circumscribed Berberis is monophyletic.
Mahonia species bear pinnate leaves long with 3 to 15 leaflets, and flowers in racemes which are long. Several species are popular garden shrubs, grown for their ornamental, often spiny, evergreen foliage, yellow flowers in autumn, winter and early spring, and blue-black berries. The flowers are borne in terminal clusters or spreading racemes, and may be among the earliest flowers to appear in the growing season. The berries are edible, and rich in vitamin C, though with a very sharp flavor. Although edible, the plants contain berberine, a compound found in many Berberis and Mahonia species, which can cause vomiting, lowered blood pressure, reduced heart rate, lethargy, and other ill effects when consumed in large quantities.
The genus name, Mahonia, derives from Bernard McMahon, one of the stewards of the plant collections from the Lewis and Clark expedition. The type species of the genus is M. aquifolium.

Species

The following list includes all currently recognized species of the genus Mahonia as accepted by Tropicos, Missouri Botanical Garden as of February 2016, sorted alphabetically. For each, binomial name is followed by author citation.