5. Macrosamanea pubiramea (Steud.) Barneby & J.W.Grimes var. pubiramea, Mem. New York Bot. Gard. 74(1): 194. 1996. Figs. 2 f-h; 5a-e

Sc a ndent sh r ubs, 2–3. 5 m t a l l; you ng branches cylindrical, leticellate, puberulent to uncinate. Stipules 0.5–2.3 mm long, triangular to narrowly triangular, persistent. Leaves bipinnate; petiole 0.6–2 cm long, cylindric; rachis 9.5–19 cm long, cylindrical; leaf nectary present on petiole and between nearly all of the leaflet pairs, sessile, patelliform, circular to semicircular; pinna pairs 7–13; leaflets in 18–25 pairs per pinna, congested, 10–13.3 × 0.3–0.48 cm, rhombic-lanceolate, base asymmetric, apex obtuse, mucro present, adaxial and abaxial surfaces glabrous, margins glabrous to glabrescent. Inflorescences capituliform, globose, axillary, 1–3; peduncle 1–2.3 cm long, puberulent; rachis 3–4 mm long, clavate; basal bracts 1.8–2 mm long, triangular, persistent, nectary present, 1.3–2 × 1.8–2 mm, sessile, lentiform, medial and terminal bracts 1–1.4 mm long, oblong to oblanceolate, caducous; flowers 16–29, homomorphic. Flowers subsessile; calyx infundibuliform, puberulent, greenish, tube 6–7.2 mm long, lobes 1–1,7 mm long, acute; corolla narrowly infundibuliform, greenish to white-vinaceous, puberulent, tube 17–19 mm long, lobes 5.6–7 mm long, acuminate; androecium tube 29–32 mm long, exerted, stamens 75–84, 24–29 mm long, white to white-vinaceous; nectary disc present, 0.8–1 mm tall; gynoecium 1-carpellate; ovary 2.4–3 mm long, glabrescent, styles 55–61 mm long, glabrous, stigma funnelform. Fruits not seen. Examined material: Alta Floresta, RPPN Cristalino, próximo ao Cristalino Lodge, 09°35’52”S, 55°55’47”W 31.X.2023, fl., J. M. Fernandes et al. 1993 (HERBAM); 31.X.2023, fl., J. M. Fernandes et al. 1994 (HERBAM). Novo Mundo, 09°26’59”S, 55°49’52”W, 1.XI.2023, fl., J. M. Fernandes 2035 (HERBAM).

This species occurs in Brazil, Colombia, Guyana, French Guiana, Suriname, and Venezuela (Barneby & Grimes 1996; GBIF 2023a). In Brazil, it had been recorded in the states of Acre, Amazonas, Amapá, Pará, Rondônia and Roraima in areas of igapó forest, terra firme forest, and várzea forest (Morim 2010; Silva 2024). In Mato Grosso, M. pubiramea var. pubiramea has been recorded in the municipalities of Alta Floresta and Novo Mundo in riparian and várzea forests on the margins Rio Cristalino (Fig. 4). Among the other states where this species occurs, this variety has not been recorded in Rondônia (Silva 2024).

Macrosamanea pubiramea is similar to M. duckei (Huber 1909: 377) Barneby & J.W. Grimes (1996: 193) by the presence of basal bracts with nectaries, leaves with six or more pinna pairs, leaflets straight or obscurely sigmoid and inflorescences capituliform with a rachis 2.5–6.5 mm long, but differs by the larger flowers with a calyx 6.5–12 mm long, corolla 18–34 mm long and 80–106 stamens, while M. duckei has small flowers with a calyx 4.5–7.5 mm long, corolla 11–16 mm long, and 45–50 stamens (Barneby & Grimes 1996). We identified plants of Macrosamanea pubiramea var. pubiramea in the region of Cristalino based on the presence of leaflets that are rhombic-lanceolate and 3–4.8 mm long, with a short segment between leaflets.