Martiodendron elatum (Ducke) Gleason var. elatum

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 : 31

Martiodendron elatum (Ducke) Gleason var. elatum

Diagnosis: — Martiodendron elatum var. elatum differs from M. elatum var. occidentale by its (8–)9(–10), generally larger and wider leaflets, the terminal ones (6.5–)9–15(–17) × (2.2–) 3.5–5 cm, 2.4–3.2(–3.6) times longer than wide; sometimes unstable number of stamens, ranging from 5(–7), 0–5 staminodes; wider fruits [(4–) 6–8 cm wide and 1.8–2.6 times longer than wide], and more strongly curved fruits, with one or both sides generally curved, sometimes fruits weakly falcate ( Figures 3–4 ).

Distribution, Habitat and Ecology: —The variety is distributed in two areas, with an apparent significant disjunction between them, although parts of the intervening area remain poorly collected. The first area is in the south-central Brazilian Amazon, mainly in the mid to upper basin of the Tapajós River in southwestern Pará, but also in adjacent parts of southeastern Amazonas, in the municipality of Borba. Ducke (1948) indicated that it also occurs in the Serra do Parintins, near the town of Santa Julia in western Pará, just south of the Amazon River, but there are no specimens from this area. The second area of distribution is in the upper drainage of the Rio Negro in extreme northwestern Amazonas, Brazil, and southern Venezuela ( Figure 15 ).

Although Ducke (1922) indicated that this taxon was common on the banks of the upper Tapajós River, very few collections from the region exist, probably reflecting low collecting effort in the area. However, during a recent expedition in and around the Parque Nacional da Amazônia, we located only one individual along the Tapajós River. Moreover, the variety also seems uncommon in the northern distribution area; we have located only 14 specimens from Venezuela and northwestern Amazonas, Brazil, and only seven specimens from Pará and southeastern Amazonas. Before our expedition in 2020, the taxon had not been collected in Pará since 1952. Besides the two populations of M. elatum var. elatum appears to be geographically isolated, the southeastern population of M. elatum var. elatum and M. elatum var. occidentale have an almost continuous distribution south of the Amazon basin, with possible gene exchange still taking place between them ( Figure 15 ).

Taxonomic Comments: —Although the two populations of M. elatum var. elatum are apparently geographically isolated, one in Upper Rio Negro another in the southwest of Pará, no morphological variation was found between the two populations. Zimmerman et al. (2017) indicated that M. elatum has partial conation of stamens. However, we observed completely free stamens in almost all specimens; only rare anomalous flowers in two specimens of the variety elatum had two of the six or seven stamens deformed and fused. Koeppen & Iltis (1962) also stated the variable number of stamens in this variety. Although anomalous quantities of stamens (reaching sometimes seven and with a variable number of staminodes) are, indeed, only found in this taxon among all others in the genus, we could observe here, with a greater number of specimens analyzed, that even within M. elatum var. elatum , this character is rare and the majority of specimens and the majority of flowers in each specimen present five stamens.

Additional Specimens Examined (23 specimens:) — BRAZIL: Amazonas: Borba: BR230 , estrada Transamazonica, 1–5 km upstream from Sucunduri , 6°50’S 59°0’W. Tree, 5 m, 9-V-1985, Henderson, A. 418 ( F; INPA; K; MG; NY; US); Santa Isabel do Rio Negro: acampamento da cachoeira do rio Tucano. Árvore 12 m × 15 cm, 23-VIII-2002, Silva, J. B. F. 1123 ( IAN); Barcelos: environs of the Yanomami village of Watoriketheri , 62°49’W 1°31’N. Árvore, 40 m + × 80 cm, VIII-1994, Milliken, W. 2054 ( K); Árvore , 20 m × 25 cm VIII-1994, Milliken, W. 2076 ( K); Cuiufite, rio Demeni. Árvore , 18 m, 17-X-1952, Fróes, R. L. 28977 ( IAN; NY); Pará: Alto Rio Tapajós, Itaituba, Parque Nacional da Amazônia. Árvore , 35-40 m, 27-I-2020, Falcão, M. J. 212 ( RB; NY; HSTM); Falcão , M. J. 214 ( RB; NY; HSTM); Vila Nova, perto da cachoeira do “Chacor ã o”. Árvore , 25 m × 30 cm, 22-I-1952, Pires, J. M. 4003 ( IAN; INPA; NY; P); margem do Tapajoz , region des cataractis inferiores. 11-IX-1915, Ducke, A. s.n. MG16479 ( MG; US); 5-II-1917, Ducke, A. s.n. MG16724 ( MG; US); 25-VI-1918, Ducke, A. s.n. MG17062 ( MG; P; R; US); “Boa Vista”. Tree, VIII-1932, Capucho 477 ( F; IAN); Boa Vista on the Tapajós River . V-VI-1929, Dahlgren, B. E. 121 ( F; US); VENEZUELA: Amazonas: rio Ugueto. 12-X-1951, Croizat, L. 826 ( F; NY); 2°N 64°30’W. 10-X-1951, Croizat, L. 820 ( NY); selvas pluviales del rio Pamoni, afluente del alto Casiquiare , 2°48’N 65°57’W. Arbol, 30 m, 24-IX-- 5- X-1987, Stergios, B. 11434 ( MO; NY); Atabapo: caño Jayuwapuey, afluente del rio Ocano , 3°4’N 64°40’W. Arbol , 20 m, I-1990, Fernandez, A. 6770 ( MO; NY); en la base de cuerpo circular en alto Orinoco, 2°17’N 63°47’ W. Arbol , 40 m × 160 cm CAP, X-1991, Marin, E. 1771 ( MO; NY); 5 km al norte de la desembocadura del Rio Orinoquito en el Rio Orinoco, 2°24’N 64°24’W. Arbol de 36 m x 140 cm CAP. Marin, E. 1635 ( NY); Tayari. 4-X-1975, Lissot, J. s.n. US 2775339 ( US); rio Ocamo , entre los Yanomami. 1978, Fuentes , E. 1083 ( US); Rio Metacuni , frente N °5 Pica N °4. Selvas riberenas y de banco, abajo del Salto “Wâniti ma”. Arbol de 25-30 m, 23-I-1990. Stergios, B. 14132 ( NY); Rio Negro , 2°16’N 63° 31’W. Arbol 30 m, 120 cm CAP, X-1991, Chaviel, A. 43 (NY).

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 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.