Inga duckei Huber, Bol. Mus. Goeldi Hist. Nat. Ethnogr.

Fernandes, José Martins, Soares, Célia Regina Araújo, Koch, Ana Kelly, Duarte, Temilze Gomes & Almeida, Anderson Alex Sandro Domingos de, 2025, New records of the mimosoide clade (Caesalpinioideae, Leguminosae) for the state of Mato Grosso, Brazil, Rodriguesia (e 00312024) 76, pp. 1-11 : 7

3. Inga duckei Huber, Bol. Mus. Goeldi Hist. Nat. Ethnogr. 5(2): 375. 1909. Figs. 2 d-e; 3f-i

Trees, 15 –17 m tall; young branches lenticellate, glabrescent. Stipules 2–3 mm long, ovate, caducous. Leaves pinnate; petiole 0.8–1.5 cm long, subcylindrical, marginate, 0.2–0.5 mm wide; rachis 6.2–10 cm long, marginate below the leaflets, 0.4–1 mm wide; nectaries sessile, cupuliform or patelliform, circular; leaflets in 4–5 pairs; terminal leaflet pair 7.2–11.6 × 2.4–4.4 cm, elliptic, rarely ovate, base cordate, apex acuminate; basal leaflet pair 3.3–5.3 × 1.8–3.8 cm, ovate, base rounded to cordate, apex acuminate; adaxial and abaxial surfaces glabrescent. Inflorescences racemose, congested, axillary, 2–4; peduncle 1.8–2.5 cm long; rachis 1–1.4 cm long. Bracts 6–8 mm long, narrowly spatulate, caducous. Flowers pedicellate, 0.6–1 mm long; calyx infundibuliform, sericeous, tube 1–1.8 mm long, lobes 0.2–0.4 mm long, cuspidate, irregular; corolla infundibuliform, sericeous, tube 3.5–4.5 mm long, lobes 1–1.2 mm long, acuminate, regular; androecium tube 4–6 mm long, included to slightly exerted, stamens 38–50, 5.5–7 mm long, white; nectary disc absent; gynoecium 1-carpellate, ovary 1.4–1.5 mm long, glabrous, style 10 mm long, stigma cylindrical. Fruit a nucoid legume, 5–18 × 2.3–2.6 cm, narrowly elliptic-oblong to elliptic, glabrescent, margins evident, surfaces open, brilliant, transversally striate; seeds not seen.

Examined material: Alta Floresta , margem do Rio São Manoel, porto de areia, 09°38’23”S, 56°00’41”W, 24.XII.2023, fr., J. M. Fernandes 2052 ( HERBAM). Novo Mundo , Reserva Particular do Patrimônio Natural ( RPPN) Cristalino, margem do Rio Cristalino, 2.XI.2023, fr., J. M. Fernandes et al. 2042 ( HERBAM). ColÍder, canteiro de obras da Usina Hidrelétrica ColÍder, 10°58’47”S, 55°45’42”W, 7.IV.2011, fr., C. R. A. Soares et al. 3290 ( HERBAM); fl., C. R. A. Soares et al. 1329 ( HERBAM) .

This species is restricted to Brazil and Peru ( Pennington 1997). In Brazil, it was only known to occur in igapó forests in the state of Amazonas ( Pennington 1997; Garcia & Bonadeu 2024). We increase its distribution to Mato Grosso where is occurs in the municipalities of Alta Floresta, Novo Mundo and ColÍder in areas of várzea, riparian and gallery forests on the margins of the Cristalino, São Manoel, and Teles Pires rivers ( Fig. 4 ).

Inga duckei is morphologically similar to I. alba ( Swartz 1788: 85) Willdenow (1806: 1013) and I. pezizifera ( Pennington 1997) . It differs from I. alba by the non-alate leaf rachis, leaflet shape, longer peduncles, pedicellate flowers, pubescence, and wider fruit; it differs from I. pezizifera by the smaller leaf nectaries, smaller leaflets with a cordate base, and shorter flower rachis ( Pennington 1997). According to the same author, the ecology of I. duckei also differs. It is restricted to inundated forest, while I. alba and I. pezizifera occur in terra firme forest.

Figures

Figure 2 – a-c. Inga bourgonii – a. leaf; b. inflorescences; c. fruit. d-e. I. duckei – d. leaf; e. fruit. f-h. Macrosamanea pubiramea var. pubiramea – f. habit; g. leaves; h. inflorescences. i-k. Piptadenia pteroclada – i. trunk with suberose wings and aculeus; j. leaf; k. fruits. (Photographs: a-g, i-k. J.M. Fernandes; h. A.K. Koch).

Figure 4 – Distribution of Inga bourgonii, I. cinnamomea, I. duckei Inga huberi, Macrosamanea pubiramea var. pubiramea and Piptadenia pteroclada in Mato Grosso.