Combretum laxum
Description
Woody liana to 35 m (often much less), stems up to 14 cm diam., in the absence of support a shrub with scandent or decumbent long branches or a shrub to 3 m; ‘combretaceous hairs’ often very scarce) and peltate scales present. Leaves opposite, chartaceous or subcoriaceous, mostly elliptic to elliptic-oblong, less often narrowly or broadly so, or sometimes ovate-elliptic to narrowly so, (2-)4-24.5 x 1.4-13 cm,
apex mostly gradually or abruptly shortly to long acuminate, less often acute or obtuse to rounded, base mostly broadly cuneate to rounded, less often acutely cuneate or subcordate to cordate, mostly hairless or almost so, less often pubescent or even densely so below and sparsely so above, moderately to rather densely lepidote below, sparsely or very sparsely so above, scales usually inconspicuous to naked eye, dark or whitish; venation usually eucamptodromous-brochidodromous, sometimes eucamptodromous or brochidodromous, secondary veins 6-10(-14) pairs, moderately prominent, tertiary veins irregularly to regularly percurrent, slightly prominent, higher order veins distinct, slightly prominent; petiole 0.3-1.1 cm long, glabrous to moderately pubescent, inconspicuously lepidote. Inflorescence sparsely to extensively branched, slender, in opposite pairs in leaf-axils, 3-9.5 cm long, usually aggregated into terminal panicles up to 33 cm long, at lower nodes in axils of normal leaves (often fallen by fruiting), at upper nodes without subtending leaves, glabrous to densely pubescent or rarely tomentose, inconspicuously lepidote; flowers borne densely, less often spaced out, on rhachis. Flowers 4-merous, 2.3-3.8(-5) mm long, glabrous to rather densely pubescent and moderately to densely but usually very inconspicuously lepidote outside; lower hypanthium 0.8-1.8(-2.3) mm long, without or with very short pedicel-like region, more densely pubescent and lepidote than upper hypanthium but sometimes hairless,upper hypanthium deeply cupuliform, 1.4-2(-2.8) x 1.5-3(-3.5) mm, subglabrous to pubescent inside (degree not correlated to pubescence outside); calyx lobes erect, 0.1-0.4 mm long, apex subacute to obtuse; petals 4, patent to reflexed at full anthesis, broadly spathulate with limb transversely oblong-elliptic, 0.8-1.8 x 1-1.5(-2) mm, well exceeding calyx lobes, apex rounded, truncate or irregular, basal claw 0.1-0.5 mm long, glabrous; stamens 8, well exserted, filaments 3-4.7(-6.4) mm long; disk usually sparsely pubescent at margin, without or with narrow free margin up to 0.15 mm long; style (3.1-)4-5.3(-6.6) mm long, usually exserted about as far as stamens. Fruit very variable. Broad-winged fruit: densely but minutely lepidote on body, more sparsely so on wings, glabrous to fairly densely pubescent, especially on body, 1.4-3.8 x 1.3-3.1 cm, broadly elliptic to orbicular in side view, apex retuse, base retuse (often very strongly), slender pseudostipe 0.2-1 cm long, body without spongy tissue, wings 4, thin and flexible, 0.5-1.3 cm wide.Narrow-winged fruit: hairless to tomentose with hairs denser on body, moderately to densely but minutely lepidote especially on body, 1.4-3(-4) x 0.6-1.2 cm, ovate to narrowly to broadly elliptic or oblong-elliptic in side view, apex acute or acuminate to rounded or truncate, sometimes minutely apiculate, base rounded to narrowly cuneate, thick to narrow pseudostipe 0-0.6 cm long, body much thickened with spongy tissue, wings or ridges 4, stiff, 0.05-0.25 cm wide, sometimes spirally twisted and/or markedly crispate. Scales ca. 40-60 (-70) µm diam., usually whitish, marginal cells 8-11.
apex mostly gradually or abruptly shortly to long acuminate, less often acute or obtuse to rounded, base mostly broadly cuneate to rounded, less often acutely cuneate or subcordate to cordate, mostly hairless or almost so, less often pubescent or even densely so below and sparsely so above, moderately to rather densely lepidote below, sparsely or very sparsely so above, scales usually inconspicuous to naked eye, dark or whitish; venation usually eucamptodromous-brochidodromous, sometimes eucamptodromous or brochidodromous, secondary veins 6-10(-14) pairs, moderately prominent, tertiary veins irregularly to regularly percurrent, slightly prominent, higher order veins distinct, slightly prominent; petiole 0.3-1.1 cm long, glabrous to moderately pubescent, inconspicuously lepidote. Inflorescence sparsely to extensively branched, slender, in opposite pairs in leaf-axils, 3-9.5 cm long, usually aggregated into terminal panicles up to 33 cm long, at lower nodes in axils of normal leaves (often fallen by fruiting), at upper nodes without subtending leaves, glabrous to densely pubescent or rarely tomentose, inconspicuously lepidote; flowers borne densely, less often spaced out, on rhachis. Flowers 4-merous, 2.3-3.8(-5) mm long, glabrous to rather densely pubescent and moderately to densely but usually very inconspicuously lepidote outside; lower hypanthium 0.8-1.8(-2.3) mm long, without or with very short pedicel-like region, more densely pubescent and lepidote than upper hypanthium but sometimes hairless,upper hypanthium deeply cupuliform, 1.4-2(-2.8) x 1.5-3(-3.5) mm, subglabrous to pubescent inside (degree not correlated to pubescence outside); calyx lobes erect, 0.1-0.4 mm long, apex subacute to obtuse; petals 4, patent to reflexed at full anthesis, broadly spathulate with limb transversely oblong-elliptic, 0.8-1.8 x 1-1.5(-2) mm, well exceeding calyx lobes, apex rounded, truncate or irregular, basal claw 0.1-0.5 mm long, glabrous; stamens 8, well exserted, filaments 3-4.7(-6.4) mm long; disk usually sparsely pubescent at margin, without or with narrow free margin up to 0.15 mm long; style (3.1-)4-5.3(-6.6) mm long, usually exserted about as far as stamens. Fruit very variable. Broad-winged fruit: densely but minutely lepidote on body, more sparsely so on wings, glabrous to fairly densely pubescent, especially on body, 1.4-3.8 x 1.3-3.1 cm, broadly elliptic to orbicular in side view, apex retuse, base retuse (often very strongly), slender pseudostipe 0.2-1 cm long, body without spongy tissue, wings 4, thin and flexible, 0.5-1.3 cm wide.Narrow-winged fruit: hairless to tomentose with hairs denser on body, moderately to densely but minutely lepidote especially on body, 1.4-3(-4) x 0.6-1.2 cm, ovate to narrowly to broadly elliptic or oblong-elliptic in side view, apex acute or acuminate to rounded or truncate, sometimes minutely apiculate, base rounded to narrowly cuneate, thick to narrow pseudostipe 0-0.6 cm long, body much thickened with spongy tissue, wings or ridges 4, stiff, 0.05-0.25 cm wide, sometimes spirally twisted and/or markedly crispate. Scales ca. 40-60 (-70) µm diam., usually whitish, marginal cells 8-11.
Distribution
America present, Argentina present, Guianas present, Northern America
Most abundant species of the family in America but slightly less widely distributed than C. fruticosum , extending from Mexico to ca. 28° S in Argentina; several hundreds of specimens from the Guianas (many in GU, SU and FG).
Notes
Extremely variable species, particularly in pubescence of leaves and inflorecences (from densely pubescent to glabrous), leaf shape, and notably fruit morphology, but these three lines of variation are not correlated. The fruits vary from having four wide papery wings and a slim body to having four narrow ridges and a thick spongy body, with all intermediates. The development of a spongy mesocarp is associated with water rather than wind dispersal. Galled fruits are very common, where they occur often all the fruits on a specimen are galled. The commonest type of gall is a 4-lobed body less than 1 cm long taking the place of each fruit, and easily mistaken for the latter. In sterile material the very small scales on the lower leaf surface separate this species from sections Thiloa and Combretum .
See note underC. fusiforme .
See also underC. pyramidatum .
See note under
See also under