Xylocarpus J.Koenig

Semi-evergreen maritime trees. Twigs lenticellate, cicatrose. Leaves paripinnate with (l–)2–4(–5) pairs of leaflets, entire, glabrous. Flowers unisexual in short axillary thyr-ses. Calyx 4-lobed to about the middle, valvate. Petals 4, contorted and much longer than the calyx in bud. Staminal tube margin with 8 suborbicular, retuse or shallowly and irregularly divided lobes; anthers 8, included. Disk cushion-shaped, beneath or surrounding and united with ovary, red. Ovary 4-(or 5-)locular, each locule with 3 or 4(–6) ovules; style short, stylehead discoid, its margin crenellate and its upper surface with four radiating stigmatic grooves. Fruit a large pendulous subspherical capsule, tardily dehiscing by 4 (5) leathery valves from apex. Seeds 5–20, large, irregularly tetrahedral or pyramidal, outermost surface convex, attached to central columella, with aerenchymatous (?sarcotestal) coat; embryo with the radicle lying above the hilum; ger-mination cryptocotylar, the numerous subulate cataphylls verticillate or spirally arrang-ed; true leaves simple, entire, later ones trifoliolate (rarely first ones thus). 2n = 52.

UsesThe wood of all three species is rich redbrown in colour and hard. When large enough pieces are available they are used for boat-building (still practised in the Maldives, where X. rumphii is largely used, Balasubramaniam) and construction as well as for good quality furniture, but the trees are often left in mangrove from which trees of other species have been removed for the production of charcoal. Details of the wood structure are provided by Panshin [ Panshin Philipp. J. Sc. 48 1932 150 ]and T.D. Penn. & Styles (l.c.), where details of palynology are also presented. The bark is used in tanning. Of the commercial tan barks in the Philippines Filamor [ Filamor Philipp. J. Anim. Ind. 26 1965 43 ]reports that Xylocarpus has the highest percent-age (13.13) tannin in the bark. With leather, it penetrates rapidly and gives a firm tex-ture and a tan colouration. It gives cloth an umber or red colour. Mixed with the tanbark of Ceriops, fixed with potassium dichromate, and coaltar fixed with petrol, the bark (‘nigi’) has been found to be the most efficacious preservative for fishing nets in the Philippines [ Bersamin et al. Philipp. J. Sc. 96 1967 143 ]. A number of medical uses have been gathered together by L.M. Perry [ L.M. Perry Med. Pl. E & SE Asia 1980 263 ]: all parts of the plant are astringent, especially the roots and bark, which has been widely used in the treatment of dysentery. Plants have been raised in Florida [ Gill Bull. Fairchild Trop. Gard. 24 3 1969 10 ].