+Laburnocytisus adamii (also known as Adam's laburnum or broom laburnum) is a horticultural curiosity; a small tree which is a graft-chimaera between two species, a laburnum, Laburnum anagyroides, and a broom, Chamaecytisus purpureus (syn. Cytisus purpureus), which bears some shoots typical of the one species, some of the other, and some which are a peculiar mixture of both "parents". This binomial name is written as if it were one species, but strictly speaking it is not one species but two. The plus sign (+) indicates its unusual origin. The plant can also be described by the formula Laburnum anagyroides + Chamaecytisus purpureus.