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Shrubs, or trees to 25 m; young branches densely hairy, rarely glabrous, glabrescent, lenticellate (occasionally lenticels absent). Leaves spirally arranged, chartaceous to rigidly coriaceous, long to short petiolate, heterophyllous, compound or pinnatisect when juvenile and sometimes in fertile/ adult state, adult leaves generally simple, glabrous to densely tomentose, quickly glabrescent above, glabrescent or persistent beneath, hairs erect or appressed, whitish or yellowish to ferrugineous or rufous. Compound leaves imparipinnate; leaflets 2-15 pairs, sessile to short-petiolate, asymmetrical, opposite or alternate, margin serrate, rarely entire. Simple leaves short- to long-petiolate, shape various, margin entire to strongly serrate, revolute or not; venation conspicuous to obscure, plane to slightly raised above, generally more prominent beneath, eucamptodromous to semicraspedodromous, occasionally brochidodromous, tertiary venation reticulate, midvein usually reaching leaflet apex. Inflorescences unbranched, pseudo-racemose, axillary or terminal, generally solitary, glabrous to densely tomentose or velutinous; flower-pair axis (peduncle) absent, rarely present; common bracts subtending flower-pairs caducous; flowers pedicellate. Flower buds elongate or elongate-pyriform, opening apically by elongation of style. Flowers actinomorphic; all tepals recurving at right angles at anthesis, glabrous to densely tomentose outside, glabrous within; filaments adnate to perianth to different degrees, generally almost entirely fused, free part ribbon-like, anthers linear to oblong; hypogynous glands 4, fleshy or scale-like, well separated, sometimes fused at base or rarely appearing as a continuous ring; ovary subsessile, glabrous to densely pubescent, sometimes flattened longitudinally and weakly keeled, style erect, claviform, stigma an apical slit, ovules 2, orthotropous, pendulous. Fruit a 1-2-seeded follicle, longitudinally flattened, commonly constricted at base and apex, apex sharp and straight, or strongly curved towards unsutured side, style occasionally persistent; seeds compressed, winged, seed central to wing.


Amazon Basin to SE Brazil present, Andes present, Argentina present, C America present, Guianas present, Guyanan Shield present, Northern America, Southern America: Bolivia (Bolivia present)
Widespread genus of 33 species from Mexico, throughout C America, to Bolivia and Argentina, including the entire Andes, the Guyanan Shield and the Amazon Basin to SE Brazil; in the Guianas 5 species.


The name Roupala is derived from the vernacular name “roupale” used in French Guiana.


Growth rings indistinct or absent.
Vessels diffuse, solitary and clustered into groups of up to 3, rarely more forming tangential bands; 13-19 (16) per mm2, circular, 38-128 (84) μm wide. Perforation plates simple. Intervessel pits alternate and usually bordered. Vessel-ray pits alternate.
Rays uniseriate and multiseriate (6-26 cells wide), 1-4 per mm. Uniseriate rays composed of upright cells and 1-5 cells in height. Multiseriate rays composed of procumbent body cells and 1-3 rows of upright and/or square marginal cells. Multiseriate rays 175-1075 (493) μm wide and over 1mm in height, often appearing as an aggregate, dissected by axial elements. Sclerotic ray parenchyma cells present in the multiseriate rays of R. suaveolens whereas silica bodies present in the ray and axial parenchyma cells of R. montana ().
Axial parenchyma present in narrow tangential bands 1-3 cells wide in R. suaveolens and 2-5 cells wide in R. montana and 3-5 per mm; up to 10 cells per strand. Ground tissue of non septate fibres with thick walls and rare simple to minutely bordered pits on the radial walls.


Multiseriate rays are wider in R. montana (up to 26 cells or 1075 μm) relative to R. suaveolens (up to 13 cells or 625 μm). Silica bodies have also been recorded in the axial parenchyma cells of R. montana according to the InsideWood database. Roupala is also described as having bordered pits on the fibres (Détienne & Jacquet 1983). Fibre pits are also noted on tangential walls but less numerous than those on the radial walls (Mennega 1966). Especially during the 19th century, the orthographic variant spelling 'Rhopala' was generally used.