An evergreen shrub of dwarf, compact growth, up to 3 ft high; shoots angled, armed with triple spines. Leaves elliptic or inclined to oval, 1 to 21⁄2 in. long, 1⁄2 to 3⁄4 in. wide, pointed, cuneate at the base, margins spiny-toothed, dark glossy green above, waxy white beneath; stalk 1⁄10 to 1⁄5 in. long. Flowers borne either solitary, in pairs, or in threes on short shoots bearing a terminal cluster of leaves, each up to 1 in. across, pale to creamy yellow. Fruits egg-shaped to nearly oblong, up to about 5⁄8 in. long by 2⁄5 in. wide, blue-black but covered with a grey-white bloom.
Native of S.E. Tibet, discovered and introduced by Kingdon Ward in 1924. It belongs to the Wallichiana section of the genus which is commonly represented in gardens by B. hookeri. It flowers in May and is well marked by its large flowers and dwarf habit (Kingdon Ward found it 'growing in masses 1 ft high'). It was given an Award of Merit at Vincent Square, 19th May 1942.
B. × bristolensis Ahrendt – A hybrid of B. calliantha, the other parent being in all probability B. verruculosa, which it resembles in having warty stems and solitary flowers. In leaf it is nearer to the first-named parent.