Branches develop from reddish brown, with ridges lengthways and very fine grains when young, to yellowish gray, circular in cross-section with persistent half circle-shaped leaf scars, and often with corky outgrowths.

Pure B. serratodentata leaves are 2½-4 times longer than wide, with more than ten teeth on each side, while spines on the branches are rare.

B. lagenaria described by Jean Louis Marie Poiret in 1808, and B. subarctica described by Michel Gandoger in 1913 both are now regarded as synonyms of B. ilicifolia.

Like almost every Berberis species in South-America, B. ilicifolia belongs to the subgenus Australes, characterised by simple, evergreen leaves and glaucous, purplish to black berries.

[2] Within that subgenus, B. ilicifolia forms a group with B. chilensis, B. litoralis, B. valdiviana, B. darwinii, B. trigona, B. serratodentata, B. negeriana, and probably B. laurina.

[3] The filaments are tactile, i.e. they suddenly jerk upright when touched, with the result that visiting insects will be showered with pollen.