Martiodendron elatum (Ducke) Gleason, 1935

Falcão, Marcus José De Azevedo, Torke, Benjamin M., Garcia, Gabriel Santos, Silva, Guilherme Sousa Da & Mansano, Vidal De Freitas, 2023, A Taxonomic Revision of the Neotropical Genus Martiodendron (Fabaceae: Dialioideae), Phytotaxa 578 (1), pp. 11-56 : 26-31

Martiodendron elatum (Ducke) Gleason . Phytologia 1(3):141 (1935).

≡ Martiusia elata Ducke. Archivos do Jardim Botânico do Rio de Janeiro 3: 116–117 (1922).

Type:— Brazil: Pará: alto Rio Tapajós, Bella Vista.Arbor magna floribus aureis legumine ante maturitatem rubro, dernier rapide, commun, 28-XII-1917, Ducke, A. s.n. MG16853 (Lectotype: first step designated by Koeppen & Iltis [1962: 208]; second step, here designated: duplicate at MG!; Isolectotypes: INPA!; G!; K!; NY!; P!; R!; RB!; S!; U!; US!). ( Figures 3–5 ) .

Large trees (25–)30–45(–50) m tall, up to 80 cm in diameter, with or without buttresses up to 3 meters high. Leaf rachis (6.3–)10–18.5(–25.5) cm long; petiole 1–4 cm long; petiolule 2–7 mm long; leaflets (7–)9–11(–13), the blades chartaceous,the terminal ones (6–)7–15(–17) ×(1.4–)2–5(–5.5)cm,(2.4–)3–4.6times longer than wide,usually narrowly oblong, less commonly narrowly elliptical to narrowly ovate, slightly pubescent abaxially to glabrous, apex acute to acuminate or cuspidate, base almost always obtuse, rarely subcordate to truncate; axillary vegetative buds elliptical to oblong, (6–)7.7–11 × 2.3–3.6 mm, apex acuminate to cuspidate. Inflorescences thyrsoid, distichous, terminal, with elongated primary and secondary axes from which cymes form, 6.5–16(–30) × 6–22(–26) cm, usually longer than wide. Flower buds (1.3–) 1.7–2 cm long, straight, apex straight or curved; sepals 1.3–2 × 0.2–0.5 cm; petals 0.8–2(– 2.5) × 0.5–1.3 cm; stamens (4–)5(–7), staminodes 0–1(–5), when five stamens, the abaxial one commonly shorter, anthers 1.2–1.7 cm × 2 mm, glabrous or rarely with sparse, inconspicuous indumentum; gynoecium monocarpelar, rarely bicarpellary, carpel 4–6 × 2–3 mm, uniformly pubescent over its whole surface, style 6–15 mm long. Fruits oblong to strongly asymmetric, 11–17(–20.2) × (4–)4.6–8 × 0.3–0.8 cm, (1.8–)2.7–3.8 times longer than wide, red to vinaceous to purple, each wing (0.5–) 1–2 cm wide at the middle portion of the fruit, the dorsal and ventral wings equal to strongly unequal in width, seminiferous nucleus occupying the central part of the fruit, ca. 1.7–3(–4) times wider than the widest of the two wings at the middle portion of the fruit, apex obtuse to acute or cuspidate.

Distribution, Habitat and Ecology: — Martiodendron elatum is endemic to the Amazon basin, occurring in southern Venezuela, northern Bolivia, and Brazil, in Acre, southern, western, and northwestern Amazonas, Rondônia, northern Mato Grosso, and southwestern Pará ( Figure 15 ). As evidenced by specimens from nearby localities in Brazil and Venezuela, the species may be expected to also occur in Peru and/or Colombia, respectively. However, reports for Colombia by Koeppen & Iltis (1962) and by Silva et al. (2005) were based solely on a single wood sample unaccompanied by an herbarium voucher, and we have not seen any specimens to confirm the reports. Likewise, Macbride’s inclusion of M. elatum in the Flora of Peru (1943) was accompanied by a citation of a single specimen from Acre (B.A. Krukoff 5401), and no specimens from Peru.

Martiodendron elatum usually inhabits upland “terra firme” forests, including both ombrophilous and seasonal semideciduous physiognomies. It occurs less commonly along the banks of rivers and in seasonally inundated forests of river floodplains (i.e., “igapós”), and “restingas” (campinaranas). Ducke (1948) suggested that the species is more common in floodplain forests than on dry land, but this was not borne out by our survey of habitat data recorded on specimen labels. The species usually grows in clayey or sand-clay mixed soils, more rarely in sandy soils. Notes on one collection (W. Milliken 2054) indicate that the species provides food for parrots and peccaries.

In terms of rainfall, M. elatum has a wider habitat than other Amazonian species of Martiodendron . It ranges from drier areas with about 1600 mm per year, similar to the areas of occurrence of M. excelsum , to wetter areas with about 2800 mm per year, similar to areas of occurrence of M. parviflorum ( Figure 16 ). Martiodendron elatum differs, however, from M. excelsum by occurring in different environments and present very different heights. M. elatum generally occurs in upland forests and reach heights of 30–45 and up to 50 meters (Oliveira, E. 5992). In contrast, M. excelsum is found mainly in floodplain forests, along riverbanks, and in campinaranas, and is not known to exceed 25 meters in height. Croizat mentions that, in Venezuela, M. elatum is one of the largest trees in the dense forests (Croizat, L. 826).

Le Cointé (1947) reported the occurrence of M. elatum in the former state of Goiás, possibly in an area currently belonging to the state of Tocantins, but only M. mediterraneum , a similar species, occurs there. Silva et al. (2005) reported M. elatum var. elatum for the states of Maranh ã o and Tocantins, but only M. mediterraneum with which M. elatum is often confused, occurs in those two states. The same authors cited M. elatum var. elatum for Rondônia, based on the specimens Ulisses 12980 and Paulino-Filho 158. However, we found that these two specimens represent M. elatum var. occidentale and note that the authors had annotated then as such on the sheets. As for M. elatum var. occidentale, Silva et al. (2005) indicated that Ducke reported the taxon in “southeast Pará ”, in Parintins Mountains and Tapajós River. It should be noted, however, that these two localities are in western Pará, and that Ducke’s mention of them (1922; 1935; 1948) was in reference to M. elatum var. elatum . The only localities referenced by Ducke for M. elatum var. occidentale are in the states of Acre and Amazonas.

Etymology: —The species was named by Ducke from the Latin elatus which means very tall, due to the size of the trees. This species, together with M. parviflorum , are the tallest of the genus, reaching 50 meters tall.

Phenology: —The species flowers from January to April and more rarely from November to June in southern Amazonia, and from August to October in northern Amazonia. Fruits are generally present from April to September, more rarely until December.

Uses: —The wood of M. elatum is used in civil construction and the manufacture of furniture, although its hardness makes it difficult to work ( Ducke, 1948). Martiodendron elatum is the only species of the genus to be harvested for its wood on a commercial scale ( Santini Junior 2013; Roitman 2021). Like other species of the genus, it holds great ornamental potential due to its abundant and beautiful flowers and fruits.

Conservation: — M. elatum is the most widespread species of the genus, and it occurs in a number of protected areas, such as Parque Nacional Parima-tapirapecó in Venezuela, Parque Nacional Pico da Neblina, Parque Nacional da Amazônia, Reserva Extrativista Chico Mendes, Reserva Florestal de Humaitá, Reserva Biológica Jaru and the Yanomami reserve in Brazil. It was once considered abundant in some areas of Acre (Santos, J.V. 164 in 1978) and in the upper Tapajós ( Ducke, 1922) but only 18 collections were made after 2000. It has an estimated EOO of 1,682,727 km 2, and we suggest that it be assigned to the IUCN Red List category of least concern. However, unlike other species of the genus, M. elatum is frequently harvested for its timber, it being considered to be one of the 100 most used tree species in Brazil ( Santini Junior 2013; Roitman 2021). Thus, some populations of the species may be threatened by overharvesting. As for its two varieties, M. elatum var. elatum has an estimated EOO of 719,052 km 2, but has a great disjunction between two considerably smaller populations. In contrast, while that of M. elatum var. occidentale is 620.264 km 2, also indicating Least Concern However, given increasing deforestation, even in legally protected areas, and especially in the southern Amazon where var. occidentale occurs ( Davidson et al., 2012; Potapov et al., 2017; Montibeller et al., 2020; INPE, 2021) we recommend that the conservation status of M. elatum and its varieties be studied in more depth.

Vernacular Names: —Angelin-da-mata, Coraç ã o-de-negro, Falsa-violeta, Groçaí-mangalô, Groçaí-rosa, Jitai, Jitai-cica, Jutaicica, Jutaicica-tamarindo, Jutai-rosa, Jutaí-seca, Jutahy-sica, Martiúsia, Muirapichuna, Pororoca, Rouxinho, Tamarino, Tamarindo , Tórem-tamarino and Violeta ( Brazil). The names Jitai, Pororoca, Tamarindo and their variations are also used for Dialium , a closely related genus of Dialioideae . The name Coraç ã o de Negro is also used for the genus Vatairea , another Fabaceae .

Nomenclatural Comments: —In the protologue of M. elatum, Ducke (1922) cited several gatherings without specifying a holotype. Koeppen & Iltis (1962) subsequently designated MG 16853 as the lectotype; however, this herbarium number is not a unique identifier of a single specimen, but rather an identifier of the gathering since many specimens from the same gathering, which can be considered duplicates, were distributed from the Museu Goeldi to other herbaria, each with a label of the Museu Goeldi bearing the same number. While we suspect that Koeppen & Iltis (1962) intended to designate the sheet at MG (and not the gathering) as lectotype, their intent is somewhat ambiguous since they did not clearly specify this in the article. Thus, we deemed it necessary to make a second step in the lectotypification of M. elatum in order to firmly establish the duplicate in MG as lectotype (see Turland et al., 2018: articles 8.1–8.3, 9.3).

Taxonomic Comments: — Martiodendron elatum is a taller tree than M. excelsum , M. fluminense and M. mediterraneum . It mainly differs from the other species of the genus by having generally more and narrower leaflets and by its generally longer samaras with greater length × width ratio. It has bigger flower buds than M. parviflorum . It has generally more stamens than M. excelsum , M. mediterraneum and M. parviflorum . Differs from M. parviflorum and M. excelsum by the glabrous anthers and from M. excelsum by the fully pubescent carpels and longer axillary buds. Its inflorescences are thyrsoids, differentiating it from M. fluminense , and its flower buds are straight and axillary buds longer, differentiating it from M. parviflorum . The species is perhaps most similar to M. mediterraneum but the former differ from the latter also by the habitat, almost always longer axillary buds, generally more leaflets, the terminal ones generally longer and with greater length × width ratio, flower buds slightly smaller, fruits bigger and with greater length × width ratio ( Table 1 ).

Identification key for the varieties of Martiodendron elatum

1. Leaflets (8–)9(–10), generally larger and wider, the terminal ones (6.5–)9–15(–17) × (2.2–)3.5–5 cm, 2.4–3.2(–3.6) times longer than wide; fruits wider, (4–)6–8 cm wide, 1.8–2.6 times longer than wide, distinctly curved on one or both sides, sometimes weakly falcate; in south-central Amazonian Brazil (mid to upper basin of the Tapajós River of southwestern Pará and adjacent areas of southeastern Amazonas), and northwestern Amazonia, in the upper drainage of the Negro River in southern Venezuela and adjacent Brazil (northwestern Amazonas).................................................................................... Martiodendron elatum var. elatum

- Leaflets (9–)11(–13), generally smaller and narrower, the terminal ones (6–)7–11(–13) × (1.4–)2–3.2(–4.8) cm, (2.5–)3–4.6 times longer than wide; fruits narrower, 4.6–6(–7) cm wide, (2.4–)2.7–3.8 times longer than wide, with both sides relatively straight; southwestern Amazonia, in northern Bolivia and Brazil (Acre, western, southwestern, and southern Amazonas, Rondônia, and northern Mato Grosso) .......................................................................................................... Martiodendron elatum var. occidentale

Figures

FIGURE 3. Martiodendron elatum (Ducke) Gleason.A–B: Martiodendron elatum var.occidentale;A. Branch with leaf and inflorescence; B. Fruit; C–D: Martiodendron elatum var. elatum; C. Branch with leaf; D. Fruit; E. Detail of the petiolule and leaflet base; F. Detail of the axillary bud enveloped by the stipules; G. cymose subunit of the inflorescence with flower buds; H. Flower; I. Anomalous flower showing six stamens, two of them with fused filaments, petals removed; J. Stamen; K. Apex of anther with open pore; L. Carpel and part of the style; M. Longitudinally sectioned seed evidencing the cotyledon and the hypocotyl-radicular axis. A, K: Ducke, A. s.n. RB24187 and Amoêdo, S.L. 16; B, E–F: Bigio, N.C. 1684; C: Ducke, A. s.n. MG16479; D: Ducke, A. s.n. MG17062; G–H: Rodrigues, D. s.n.; I: Ducke, A. s.n. MG16853; J, L: Pereira Silva, G. 15173; M: Silva, M.G. 6201. Drawn by M. Falcão. Scale bar.A–D, M: 2 cm; E–J, L: 3 mm; K: 0.5 mm.

FIGURE 4. Martiodendron elatum (Ducke) Gleason var. elatum. A. Trunk; B. Canopy tree over 40 meters tall; C. Trunk base with detail of buttresses; D. Detail of the bark; E. Detail of leaflets; F. Detail of the exsiccatae showing the standard number of 9 leaflets per leaf; G. Detail of flower buds; H. Detail of part of the inflorescence with flowers in anthesis; I. Branches with leaves and four terminal compound thyrsoids; J. Flower; K. Detail of the flower in lateral view without the perianth, showing the gynoecium and heteromorphic stamens, note the reduced size of the filaments; L. Large typical fruit with at least one strongly curved side. Image authors: A–E, G–H: Marcus Falcão; I–K: Cássio Toledo: Falcão, M.J. 212; F. Reflora: Ducke, A. 16479; L. Reflora: Ducke, A. 17062. Scale bar. A–C: 50 cm; D, I: 10 cm; E, G–H: 2 cm; F, L: 5 cm; J–K: 1 cm.

FIGURE 5. Martiodendron elatum (Ducke) Gleason var. occidentale (Ducke) R.C. Koeppen. A. Habit of a young individual; B. Leafy branch with inflorescence, note typical leaves with 11–12 narrower leaflets; C. Larger and narrower terminal leaflets; D. Smaller and wider basal leaflets, note the axillary buds. E. Inflorescence; F. Leaf and inflorescence in exsiccatae; G. Flower in anthesis. H. Typical elongated fruit with adaxial and abaxial sides relatively straight. Image authors: A-E, G: Narcisio Bigio; F: Reflora: Ducke, A. s.n. RB24187; G: Reflora: Bigio, N. 1684. Scale bar. A: 1 m; B-D, H: 5 cm; E, G: 1 cm; F: 10 cm.

FIGURE 15. Martiodendron distribution map. Topographic map of part of the Neotropics containing all analyzed specimens of the genus separated by species and varieties. Note the occurrence of most species in areas with elevations below 200 meters, with the exception of M. mediterraneum, which generally occurs in regions of elevation 200–600 meters. Source: NASA with modifications.

FIGURE 16. Martiodendron distribution related to precipitation. Average annual precipitation map in mm of part of the Neotropical region containing all analyzed specimens of the genus separated by species and varieties in the case of M. elatum. Note the distribution of M. parviflorum and M. elatum var. elatum in wetter areas (orange color), M. elatum var. occidentale and M. excelsum generally in intermediate areas (red color), and M. mediterraneum in drier areas (green color) to intermediate areas. The preferential environments of M. fluminense in relation to humidity, despite occurring in a region with lower average precipitation (red to green color), are restricted to small areas of coastal rainforests with higher humidity. Source: WorldClim with modifications.