Recordoxylon Ducke, Trop. Woods 39: 16. 1934.

Figs 22, 23, 27

Type.

Recordoxylon amazonicum (Ducke) Ducke [≡ Melanoxylon amazonicum Ducke (= Recordoxylon speciosum (Benoist) Gazel ex Barneby)]

Description.

Unarmed trees. Stipules not observed. Leaves spiral, imparipinnate; leaflets 7-15, alternate to opposite; extrafloral nectaries absent. Inflorescence a panicle; bract 1, caducous, bracteoles 2, caducous. Flowers perigynous, bilaterally symmetrical, hypanthium campanulate; sepals 5, free; petals 5, the innermost petal yellow with white spot at the base, the others yellow, free, clawed; stamens 10, slightly heteromorphic, filaments glabrous, anthers longitudinally dehiscent; pollen unknown; ovary shortly stipitate, attached to the base of the hypanthium. Fruit oblong, straight, compressed legume, with a longitudinal rib close to the superior margin, dehiscent. Seeds elliptic-depressed, with a brownish and rugose testa.

Chromosome number.

Unknown.

Included species and geographic distribution.

Three species, R. pulcherrimum Barneby, R. speciosum, and R. stenopetalum Ducke, restricted to northern South America in the wet Amazonian forests of Brazil, Guyana, French Guiana and Venezuela (Ducke 1949; Barneby 1993; Cota 2020a; Fig. 27).

Ecology.

The genus is known from lowland tropical rainforests of the Amazon basin, on well-drained soils ("terra firme") to poorly drained soils ( “igapó” forest).

Etymology.

Named after the American botanist Samuel James Record, an important wood anatomist who observed some wood structures in R. speciosum (as Melanoxylum amazonicum; Record 1932) that led Adolpho Ducke to revise the original classification and create the new genus Recordoxylon (Ducke 1932a, 1934).

Notes.

Recordoxylon is characterised by its bilaterally symmetrical flowers, clawed petals, glabrous stamen filaments, longitudinally dehiscent anthers (Fig. 22), straight legumes and elliptic-depressed seeds with rugose and brownish testa. Morphologically similar to Melanoxylum, they can be differed by the filament indument (ferruginous-tomentose at the base in Melanoxylum vs. glabrous in Recordoxylon) and fruit morphology (slightly curved and endocarp articulated vs. straight and endocarp not articulated, respectively). The two genera are always resolved as sister taxa when they are both included in phylogenetic analyses (Haston et al. 2005; Bruneau et al. 2008; Marazzi and Sanderson 2010; Manzanilla and Bruneau 2012; LPWG 2017; Ringelberg et al. 2022).

Taxonomic references.

Barneby (1993); Ducke (1932a, 1934, 1949); Record (1932).