Goniothalamus grandiflorus is a species of rainforest tree in the Custard Apple Family Annonaceae. It is native to New Guinea and the Solomon Islands.[1] It was first formally described by Otto Warburg, a German-Jewish botanist, using the basionym Beccariodendron grandiflorum after its big, dark red flowers.[2] These flowers are borne directly on the trunk and major branches (cauliflory), the largest of all cauliflorous flowers.
It is a tree with gray smooth branches. Its young branches have rust colored hairs. Its petioles are 1 centimeters long. Its hairless, elliptical to oblong leaves are 20-25 by 8-9 centimeters with tips that taper to a short point and bases that come to a shallow point. The upper surface of leaves are bright colored while the undersides are paler. The leaves have 9-12 pairs of secondary veins emanating from their midribs. Its flowers are on 15 millimeter long pedicels. Its 3 sepals are 10 millimeters wide and 15 millimeters long and are conjoined at their margins for 5 millimeters at their base. The sepals come to a shallow point. Its flowers have 6 petals in two whorls of 3. The outer petals are 13 centimeters long (occasionally as much as seven inches (17 centimeters) in length)[3] and 12 millimeters wide. The inner surface of the outer petals have brown hairs. The inner petals are 15 by 15 millimeters. Its anthers are 2 millimeters long. Each of its flowers produces a multiple fruit, consisting of many carpels, each with 4-6 ovules. The large fruit consists of up to 40 oval, brown, wrinkled berries. each developing from one carpel, on short stalks, resembling a cluster of large grapes. Each berry in the fruit has 4-6 seeds.[4]
The pollen of G. grandiflorus is shed as permanent tetrads.[5]
Bioactive molecules extracted from its bark, leaves and flowers have been reported to have antibacterial activity against both Gram negative and Gram positive bacteria.[6]