A deciduous shrub 3 ft or sometimes more high, with rigid, crooked branchlets. The spines are very variable, some being the ordinary three-forked ones, so common in the genus; others are curiously flat and leaf-like, semi-circular or heart-shaped, the margins cut up into several long, triangular, spiny teeth. The spines on barberries, as has already been observed, are really modified leaves, and there is no species which shows their foliate character better than this. Leaves hard, rigid, not downy; variable in shape, and either obovate, oblong, or roundish; 1⁄4 to 11⁄2 in. long, with a few large spiny teeth. Flowers sweetly fragrant, produced in short umbels or clusters, deep yellow, 2⁄5 in. across. Fruit blue-black, 1⁄3 in. long.
This remarkable barberry, common enough in a wild state on the mountains of Chile, and often introduced to cultivation, is still comparatively rare. It does not flower freely, and seldom produces fruit. It is well adapted for a sunny spot in the rock garden, but has more scientific interest than horticultural value.
From the Supplement (Vol. V)
This species owes its specific epithet, ray-thorned, to the fact that the spines often have five or even seven parts, arranged like the spokes of a wheel.