Melicope balloui, also called Ballou's melicope or rock pelea, is a species of plant in the family Rutaceae. It is endemic to the Hawaiian Islands. It is threatened by habitat loss. Like other Hawaiian Melicope, this species is known as alani.[1]
This plant was described in 1913 by Joseph Rock, who named it after Howard M. Ballou, proofreader of his book on Hawaiian trees. It is a shrub or small tree with leathery oval leaves up to 10 centimeters long by 7 wide. Young twigs are coated in yellow-brown hairs. The female inflorescence contains 5 to 9 flowers; the male flower has never been seen. The fruit is a capsule about 2.5 centimeters wide.[2]
This plant is only known from the slopes of the volcano Haleakalā on Maui. There is a single occurrence containing an unknown number of plants.[3]