Mahonia - Berberis genus change
The Mahonia genus has a complex backstory. It was formerly described as a genus of approximately 70 species of shrubs or, rarely, small trees with evergreen leaves, native to North and Central America, eastern Asia and the Himalayas. Mahonia is closely related to the genus Berberis, and years of taxonomic research has resulted in species being moved back and forth between the two genera, in some cases assigning all species to either Mahonia or Berberis.
In 2023, new research revealed physical differences and genetic differences that distinguish Mahonia species from Berberis species. In particular, the leaves of Berberis species have a single leaflet at the end of each leaf stalk while the leaves of Mahonia species are ‘pinnate’ with 5-40 leaflets in opposite pairs. This would classify the three species native to BC as Mahonia aquifolium (synonym Berberis aquifolium), Mahonia nervosa (synonym Berberis nervosa) and Mahonia repens (synonym Berberis repens) but who knows what the next study will reveal! (VanDusen curator, 2023)
Photo of Mahonia aquifolium by Midge Oke from the Garden