Combretum laxum Jacq.

  • Authority

    Stace, C. A. & Alwan, A.-R A. 2010. Combretaceae. Fl. Neotrop. Monogr. 107: 1-369. (Published by NYBG Press)

  • Family

    Combretaceae

  • Scientific Name

    Combretum laxum Jacq.

  • Type

    Type. Haiti, Jacquin s.n. (holotype, BM).

  • Synonyms

    Combretum jacquinii Griseb., Combretum jacquinii f. laxum (Jacq.) Eichler, Combretum jacquinii var. laxum (Jacq.) Pulle, Combretum puberum Rich., Combretum obtusifolium Rich., Combretum mexicanum Humb. & Bonpl., Combretum odoratum Pav. ex G.Don, Combretum pulchellum Mart., Combretum ferrugineum G.Don, Combretum jacquinii var. pulchella (Mart.) Pulle, Combretum jacquinii var. pulchella (Mart.) Pulle, Combretum cordatum G.Don, Combretum ferrugineum G.Don, Combretum mexicanum var. obovatum DC., Combretum glabrum DC., Forsgardia laevis Vell., Loranthus patrisii DC., Combretum bugi Cambess., Combretum jacquinii f. bugi (Cambess.) Eichler, Chrysostachys ovatifolia Pohl, Combretum jacquinii f. ovatifolia (Pohl) Eichler, Combretum mexicanum var. laxiflorum C.Presl, Combretum variabile Mart., Combretum jacquinii f. brasiliense Eichler, Combretum variabile var. angustifolium Mart., Combretum variabile var. oblongifolium Mart., Combretum variabile var. detersum Mart., Combretum adenophyllum Mart., Combretum terminalioides Steud., Combretum viscidum Griseb., Combretum accedens Van Heurck & Müll.Arg., Combretum obtusifolium var. griseolepidotum Sagot, Combretum odoratissimum Sessé & Moc., Combretum epiphyticum Pittier, Combretum laxum var. epiphyticum (Pittier) Croat, Combretum oblongifolium Rusby, Combretum marchii Fawc. & Rendle, Combretum robinsonii Fawc. & Rendle, Combretum brunnescens Gleason, Combretum fulgens Gleason, Combretum ulei Exell

  • Description

    Species Description - Usually a woody liana, to 35 m (often much less), with stems to 14 cm diam., in the absence of support a shrub with scandent or decumbent long branches or a shrub to 3 m or even a tree to 10(20) m; combretaceous hairs (often very scarce) and peltate scales present. Leaves opposite, chartaceous or subcoriaceous, (2-)4-24.5 × 1.4-13 cm, mostly elliptic to elliptic-oblong, less often narrowly or broadly so, or sometimes ovate-elliptic to narrowly so, mostly gradually or abruptly shortly to long acuminate, less often acute or obtuse to rounded at apex, mostly broadly cuneate to rounded, less often acutely cuneate or subcordate to cordate at base, mostly hairless or almost so, less often pubescent or even densely so abaxially and sparsely so adaxially, moderately to rather densely lepidote abaxially, sparsely or very sparsely so adaxially, the scales usually inconspicuous to naked eye, dark or whitish in color according to maturity. Venation usually eucamptodromous-brochidodromous, sometimes eucamptodromous or brochidodromous; midvein moderate, prominent; secondary veins 6-10(-14) pairs, moderately spaced to distant, originating at moderately acute angles, curved along length or more or less straight proximally, moderately prominent, intersecondary veins sometimes present; tertiary veins irregularly to regularly percurrent, slightly prominent; higher order veins distinct; areolation imperfect, slightly to scarcely prominent. Petiole 0.3-1.l cm, glabrous to moderately pubescent, inconspicuously lepidote. Inflorescences sparsely to extensively branched, slender, in opposite pairs in leaf-axils, 3-9.5 cm, usually aggregated into terminal panicles to 33 cm, at the lower nodes in axils of normal leaves (often fallen by fruiting), at the upper nodes without subtending leaves, glabrous to densely pubescent or rarely tomentose, inconspicuously lepidote. Flowers borne densely, less often spaced out, on rhachis, tetramerous, 2.3-3.8(-5) mm, glabrous to rather densely pubescent and moderately to densely but usually very inconspicuously lepidote on outside; lower hypanthium 0.8-1.8(-2.3) mm, without or with very short pedicel-like proximal region, more densely pubescent and lepidote than upper hypanthium but sometimes hairless; upper hypanthium 1.4-2(-2.8) × 1.5-3(-3.5) mm, deeply cupuliform, subglabrous to pubescent inside (degree not correlated to pubescence outside); calyx lobes 0.1-0.4 mm, erect, subacute to obtuse; petals 4, 0.8-1.8 × 1-1,5(-2) mm, well exceeding calyx lobes, patent to reflexed at full anthesis, broadly spathulate with limb transversely oblong-elliptic and rounded, truncate or irregular at apex, with basal claw 0.1-0.5 mm, glabrous; stamens 8, well exserted, with filaments 3-4.7(-6.4) mm; disk usually sparsely pubescent at margin, without or with narrow free margin to 0.15 mm; style (3.1-)4-5.3(-6.6) mm, usually exserted ca. as far as stamens, glabrous; ovules 1-2(-3). Fruit very variable. Broad-winged fruit 1.4-3.8 × 1.3-3.1 cm, broadly elliptic to orbicular in side view, retuse (often very strongly) at base, with slender pseudostipe 0.2-1.1 cm, retuse at apex, densely but minutely lepidote on body, more sparsely so on wings, glabrous to fairly densely pubescent, especially on body; body without spongy tissue; wings 4, thin and flexible, 0.5-1.3 cm wide. Narrow-winged fruit 1.4-3(-4)x0.6-1.2cm, ovate to narrowly to broadly elliptic or oblong-elliptic in side view, rounded to narrowly cuneate at base, with thick to narrow pseudostipe 0-0.6 cm, acute or acuminate to rounded or truncate and sometimes minutely apiculate at apex, hairless to tomentose with hairs denser on body, moderately to densely but minutely lepidote especially on body; body much thickened with spongy tissue; wings 4, stiff, 0.05^1.25 cm wide, sometimes spirally twisted and/or markedly crispate. Scales ca. 40-60(-70) pm diam., usually whitish, circular in out- line, not scalloped at each marginal cell, divided by 8 primary radial walls and sometimes by 1-3 second radial walls; marginal cells 8-11,8 of them reaching from center to margin. Reproductive biology. Flowers (i.e., petals and filaments) white or cream-colored, ageing to yellow, very strongly scented (compared with Trifolium honey, Inga and Tilia). Despite this no pollinators have been mentioned; the small disk probably indicates rather little nectar. "Calyx" (upper hypanthium) green, often tinged reddish. Flowering and fruiting in all months; mostly flowering March to September and fruiting August to April. The broad-winged fruits are better suited to wind dispersal and the narrow-winged spongy ones to water dispersal; Croat (1974) observed that the latter are very buoyant and "no doubt largely water-dispersed" (see below under Combretum epiphyticum discussion).

  • Discussion

    Local names. Despite being the most common species of Combretaceae in the Americas, and very well collected (over 400 sheets in LTR alone), there is relatively little mention of vernacular names, probably related to its unusefulness (see below).

    Uses. Very rarely mentioned, and then only as twine (“bush-rope,” “soga”), and once potable water in hollow stem.”

    Illustrations. Figs. 33i (trichomes), 60a-d (fl), 61a-u (fr). Bezerra Loloiola & Ferreira de Sales (1998), p. 182; Eichler (1867), fl, pl. 34 (as C. jacquinii); Exell (1953), fls, p. 129 (as C. laxum, C. ulei, & C. glabrum); Ribeiro et al. (1999), p. 459, inflorescence; Stace & Alwan (1998), p. 341; St. Hilaire (1830), t. 130.

    As might be expected among several thousand herbarium specimens, some abnormal material is to be found, but the floral and other measurements very rarely fall outside the ranges given in the above description. Small-flowered plants are the most noteworthy. DeWalt & Serato 445, from La Paz, Bolivia, has flowers at the bottom end of the size range (flowers 3-3.2 mm, upper hypanthium ca. 1.5 × 2 mm) but the stamens (filaments 1.1-1.6 mm) and style (0.8-1 mm, included) are very short; the ovules are, however, well developed and the anthers are dehiscent, indicating that the flowers are probably functionally bisexual. Mori et al. 20763 and 20941, from French Guiana, have flowers of similar size to the last but the ovules appear translucent; these could be functionally male plants. The styles in the latter two plants vary from absent to ca. 2 mm and exserted. Cid Ferreira et al. 8003 from Para, Brazil, has flowers ca. 2.7 mm (upper hypanthium ca. 1.4 × 1.7 mm) and a very short style. Moreover the ovules appear translucent and the anthers blackened; the flowers are probably sterile, perhaps diseased. Prance et al. 30288, from Para, Brazil, has very small flowers not included in the above ranges: flowers 2-2.5 mm; upper hypanthium l-1.2 × l.3-1.7 mm; petals 0.7-0.8 × 1-1.1 mm; filaments 1.3-2.5 mm; style 2.2 mm, exserted. Most of the stamens and styles are broken off (presumably eaten by insects), but the anthers and ovules appear well developed.

    Combretum ulei was described by Exell from Amazonas, Brazil, and compared with C. brevistylum since at the time the types of these species were the only two specimens of section Combretastrum known with a very short included style. Whereas C. brevistylum still appears to be a distinctive taxon, the tyn of C. ulei (flowers 2.5-2.8 mm; upper hypanthium 1.2-1.5 × 1.8-2 mm; petals ca. 0.8 × 1.2 mm; stamens 2.5-3 mm; style 0.2-0.4 mm) seems to be a small-flowered C. laxum of the sort described in the preceding paragraph. The leaves of all these plants fall into the normal range of those of C. laxum, and do not closely resemble the rather distinctive small leaves of C. brevistylum.

    Only 115 (28%) of the 418 sheets in LTR possess fruits; of these 54 (48%) have narrow stiff wings and a spongy body (Fig. 61k-o) and 24 (21%) have broad papery wings and a thin body (Fig. 61a-e). Twenty-eight (24%) are classed by me as intermediate (Fig. 61f-j) and a further 10 specimens have unusually large fruits (Fig. 61p-s). Both main fruit types and the intermediates are distributed throughout much of the range of the species, but broad-winged or intermediate fruits, as well as the “unusually large” fruits, are relatively more common outside Amazonia (i.e, in Central America, West Indies, and extreme north and west and sub-Amazonian South America). The intermediate types are especially frequent in the Central American isthmus. In Amazonia narrow-winged fruits are the most common, as is usual for the genus in riverine habitats. The fruits classed by me as broad-winged are rather uniform in structure, but the narrow-winged ones (and also the intermediates) show a wide range of shape, varying from rounded at base and apex to narrowly and gradually cuneate at one or both ends, and sometimes having spirally twisted and/or markedly crispate wings. Despite the stark differences between the broad- and narrow-winged fruits, the facts that fewer than 30% of herbarium specimens bear fruits, that intermediates are not rare, and that no correlation of fruit type with any other characters has been detected, render impractical the subdivision of the species based on fruit characters. Nearly all the fruits have a distinct well-developed pseudostipe which, since the lower hypanthium is sessile at anthesis, develops after fertilization; a few pseudostipeless fruits, or those with very short pseudostipes, occur.

    Combretum epiphyticum was described by Pittier (1917) as an epiphyte that differs from C. laxum in minor features, such as pubescence and petal shape, which fall well within the variation of the latter. Croat (1974) doubted that it is ever a true epiphyte, and found that in Panama it flowers from March to April and fruits from August to September, whereas C. laxum there flowers from October to November an fruits from January to March. Moreover plants he called C. laxum have broad-winged fruits whereas those of C. epiphyticum have narrow-winged spongy fruits, obviously adapted for floating on water. Outside Panama, however, no such correlation between phenology and fruit morphology exists, and as noted above there is every intermediate between the two fruit types.

    The “unusually large” fruits are of two main types. Those from Peru, Bolivia, and French Guiana are otherwise of the intermediate-winged types, but to 3.9 × 2.2 cm in size with a pseudostipe to 0.9 cm and wings to 0.5 cm wide. The three Peruvian specimens are unusual in having densely rufous-velvety-tomentose fruits. The second type has been collected in Costa Rica, Guatemala, Brazil (Amazonas), and Ecuador; they are up to 4.7 × 2.2 cm, including a stout pseudostipe to 1.1 cm, and with 4 ridges or thick narrow wings and a thick body. The latter might represent a separate taxon. All these large fruits possess a well-developed embryo and are presumably not galled.

    Galled fruits (Fig. 61t, u) are very common; where they occur often all the fruits on a specimen are galled and this has led many workers to misinterpret the galls as the normal fruits (the opposite has also frequently occurred, e.g., in Combretum paraguariense). The most common 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. Such galls equally occur in C. pyramidatum (q.v.) and are well illustrated in that species by Eichler (1867) in his plate 31, which represents the type specimen of C. nitidum, a species actually based on this character. A second fairly common type of gall resembles a bud-like body in place of each fruit; others are small smooth ovoid structures. Leaf galls are also frequent.

    Combretum glabrum, from French Guiana, was diagnosed by De Candolle (1828b) as “ex omni parte glabrum,” confirmed by examination of the type, which bears flowers and leaves. The fruits were unknown to De Candolle. The leaves are rather long and narrow, close to the shape common in typical C. laurifolium (q.v. sub C. pyramidatum), but are chartaceous and have conspicuous veins. Rob. Schomburgk 871 (from Roraima, 1842-1843) resembles the type very closely, and again lacks fruits. The same is true of von Rohr s.n. and Richard s.n., both from French Guiana; see discussion under C. fusiforme. Another specimen in G, but not in herb. De Candolle, collected from “Cayenne” but with no other data, has been labeled type. However, it is fruiting and therefore cannot be a type. It is clearly C. fusiforme, with long oblong-ovate chartaceous leaves and fruits typical of that species. As stated by Exell (1953), "there is no certain means of separation" of C. glabrum from C. laxum, in which glabrous flowers are not uncommon. It is thus very difficult to match a particular fruit morphology to plants assignable to C. glabrum, and therefore I see no evidence for specific separation of C. glabrum and C. laxum. It appears to me that Exell’s concept of C. glabrum combined the flowers of C. glabrum and the fruits of C. fusiforme (q.v.); it is possible that he was correct, but the evidence is very weak.

    Where they are sympatric, fruiting specimens of C. mellifluum and the there much less common C. laxum are often confused; the scale sizes always distinguish them, even with only a hand lens.

    Kuntze (1898) described two varieties of C. laxum, viridulum and aurantiacum, but his “C. laxum Loefl.” in fact refers to C. fruticosum.

    Distribution and Ecology: (Fig. 59). Primarily a liana in tall evergreen wet or inundated forests, often by rivers or lakes or in swampy ground, but persisting after forest clearance and found in secondary forests, semi-deciduous or semi-evergreen forests, dry forests on slopes and hills, and savannas, also on edges of mangrove-swamps, on sandy or clayey soils or on alluvium or coastal sand, from sea level commonly to 500 m and sometimes to 1500 m (e.g., in Costa Rica). The most abundant species of the family in the Americas but slightly less widely distributed than Combretum fruticosum; from ca. 19°25' N in Jalisco, Mexico, to ca. 28° S in northern Argentina. Guaglianone (1998) noted it in Formosa, Argentina, perhaps ca. 32° S, but I have seen no specimens.

  • Common Names

    Bejuco verraco, papamiel, shinata, habéba-hanakurí-yu, supple-jack, camoora-balli, koepirisi, tototo, juti’airimbo, pombeiral, cipó bababo, cipó invasor, cipó de clareira, junu shara, bejuco seco, cayaya, yacushapana, añaya caspi

  • Distribution

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