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Trees, dioecious. Leaves alternate, distichous on the lateral branches; stipules fully amplexicaul, free; blade entire, pinnately veined. Inflorescences on spurs in the leaf axils, unisexual, discoid-capitate, involucrate. Staminate inflorescences often up to 4 together, pedunculate, the inner involucral bracts often more or less petaloid, covering the flowers before anthesis; tepals 3-7, free; stamens 2-4; pistillode absent. Pistillate inflorescences solitary, (sub)sessile; flowers several to numerous, connate and the outer ones adnate to the receptacle; tepals 3-7, the free parts conical to cushion-shaped; ovary adnate to the perianth; stigmas 2, filiform to vittiform. lnfructescences hemispherical to globose, covered with the hardened, free parts of the tepals and the inner involucral bracts; fruits embedded in the pulpy receptacle; seed large, without endosperm, cotyledons thick and equal.


Guianas present, Neotropical present
Neotropical, 20-25 species, some of them not yet described; in the Guianas 2 (or 3?) species.

Wood observation species

N. amara, N. glabra, N. guianensis


Vessels diffuse with a tendency towards a diagonal arrangement, solitary (20-80%) and in short radial multiples of 2-4, angular, round or oval, 20-45 per sq. mm, diameter 60-110 μm. Vessel-member length: 380-475 μm. Perforations simple. Intervascular pits alternate, round, oval to polygonal, 6-9 μm. Vessel-ray and vessel-parenchyma pits larger and irregularly shaped, half-bordered. Thin-walled tyloses occasionally present.
Rays uniseriate and 2-4-seriate, 6-8 per mm, up to 600-1500 μm. Heterogeneous, composed of procumbent cells, except for the uniseriate margins of 1-6 rows of square and/or upright cells. Few sheath cells. Rays sometimes vertically fused. Radial latex tubes present. Rhombic crystals sometimes present in the (marginal) ray cells.
Parenchyma paratracheal, vasicentric-aliform, occasionally locally confluent, the vasicentric ring often incomplete and lacking on the adaxial side. Strands 2-4 cells. Rhombic crystals very scarce.
Fibres septate, lumen 5-10 μm, walls 2-4 μm. Pits simple, small, restricted to the radial walls. Gelatinous fibres occasionally present. Length: 1000-1200 μm. F/V ratio: 2.4-2.8.
Vitreous silica occasionally present in the fibres and parenchyma.