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Trees, trunk basally swollen. Leaves distinctly 3-5-veined. Inflorescences axillary, 1-3(-4)-flowered clusters in the upper axils of normal or aborted leaves, or grouped on spike-like axillary short shoots. Flowers hypogynous, small, subsessile, each flower subtended by a bract and 2 minute bracteoles. Calyx cupuliform, 5-denticulate, small, persistent, not accrescent; petals 5, connate in the lower part, lobes triangular; stamens 10, filaments filiform, adnate to the basal parts of the petals, anthers subquadrate-suborbicular; ovary superior, glabrous, 2-3-locular, style very short, stigma very slightly 3-lobed. Drupe with fleshy exocarp, thin woody endocarp and 1 large seed.


Guyana endemic
Monotypic, endemic in Guyana.

Wood observation species

M. trinervis


Vessels diffuse, solitary (up to 98%) and few multiples of 2, round and slightly oval or angular, 14-15(12-19) per sq. mm, diameter 80-89(35-125) μm. Vessel-member length: 1345-1760 μm. Perforations scalariform, with 16-28 bars per perforation.
Intervascular pits rare, scalariform to opposite. Vessel-ray and vessel-parenchyma pits large, often scalariform. Tyloses sometimes present.
Rays of Krebs' heterogeneous type I, uniseriate and 2-3 seriate, the unise- riate rays composed of upright cells, the multiseriate rays composed of square and procumbent cells, but upright cells in the large uniseriate parts of these rays, 13(12-18) per mm, up to 4300 μm high.
Parenchyma scanty paratracheal, but the majority as apotracheal diffuse. Fibre-tracheids, thick-walled, lumen up to 9,urn, walls 7-8 μm. Pits borde- red, on radial and tangential walls, diameter of borders 6-8 μm. Length: 2245-2770 μm. F/V ratio: 1.57-1.67.
Crystals solitary rhomboidal, in parenchyma and in (subdivided) ray cells.