Mahonia – refers to Bernard M’Mahon or McMahon (1775-1816), an Irish-American horticulturist in Philadelphia who worked with seeds collected by the Lewis and Clark expedition and was author of The American Gardener’s Calendar (1806)

Berberis – Latinized form of the Arabian name (alburbaris) for the fruit, barberry

Native range: N. Hemisphere & S. America

Leaves:

• alternate
• occurring on short shoots from axils
• simple with spines on stems (Berberis)
• pinnately compounds with spines on leaves (sometimes classified as Mahonia)

Flowers:

• solitary or compound in umbels, racemes, or panicles
• perfect
• radial symmetry
• yellow or orange
• 6 sepals in two whorls, reflexed
• 6 petals in two whorls
• 6 stamens, anthers open with valves
• stamens spring forward when stigma touched

Fruit:

• berry
• spherical to ellipsoid
• red to dark purple

Other notes:

• shrubs to 15 ft.
• evergreen or deciduous
• usually with yellow wood or roots
• decades old debate is about whether species in Mahonia are different enough from other members of Berberis to be classified in their own genus

Species:

• Mahonia aquifolium (hollyleaved barberry, shining/tall Oregon-grape)
• Mahonia nervosa (Cascade barberry, dull/dwarf Oregon-grape)