Rhynchosia mineira L.M. Bezerra & Fort.

Bezerra, Luísa Maria De Paula Alves, Cândido, Elisa Silva, Vargas, Wanderleia De, Torke, Benjamin Marland, Lewis, Gwilym Peter & Perez, Ana Paula Fortuna, 2024, Taxonomic revision of Rhynchosia Lour. (Leguminosae, Papilionoideae, Phaseoleae) in South America, Phytotaxa 643 (1), pp. 1-67 : 44

19. Rhynchosia mineira L.M. Bezerra & Fort. -Perez, Kew Bulletin 74: 62, pg. 1-6. 2019. Type:— BRAZIL, Minas Gerais, Couto de Magalhães de Minas , BR-367 towards São Gonçalo do Rio Preto , 18°3’17.2”S, 43°26’00.2”W, alt. 995 m, 17 July 2017 (fl., fr.), T. C. Monteiro et al. 79 (Holotype: BOTU!). Iconography: Kew Bulletin 74:62, pg. 2. 2019

Subshrub prostrate, stems few-branched, pubescent, indumentum yellow, with yellow vesicular glands, but lacking bulbous-based trichomes. Stipules 5–10 × 3–4 mm, free, caducous, ovate, externally pubescent with yellow vesicular glands, but lacking bulbous-based trichomes. Leaves trifoliolate; petiole 1.8–2.8 cm long; leaf rachis 1.5–2 cm long; stipels absent; leaflets 1.8–3.3 × 1.4–3.1 cm, rounded, ovate or rhombic, surface not bullate, acuminate to rounded at apex, obtuse to rounded at base, margins entire, pilose, with yellow vesicular glands on both surfaces. Inflorescences axillary, paniculate, 6.5–25 cm long, bearing 7–11 flowers, not exceeding the length of the subtending leaf; bracts caducous; pedicels 1–2 mm long. Flowers 7–8 mm long excluding the pedicel; calyx 9–10 mm long, pubescent with yellow vesicular glands, but lacking bulbous-based trichomes, lobes lanceolate, all of them equaling or exceeding the corolla in length; standard petal 6–7 × 3–4 mm, obovate, rounded at apex, glabrous, with yellow vesicular glands, but lacking bulbous-based trichomes, claw 1–1.5 mm long, auricle ca. 0.5 mm long; wing petals 5–6.5 × 1–1.5 mm, oblong, claw ca. 1.5 mm long, auricle ca. 1 mm long; keel petals 6.5–7 × 2–2.5 mm, falcate, claw ca. 2 mm long; stamens ca. 7 mm long; ovary ca. 2 mm long, pubescent, with yellow vesicular glands. Fruits 1.5–2.1 × 0.5–0.6 cm, greenish, without constrictions between the seeds, oblong or elliptical, pubescent, with yellow vesicular glands, but lacking bulbous-based trichomes. Only immature seeds seen.

Nomenclatural and taxonomic notes: — Rhynchosia mineira is characterized by its corymbiform inflorescences not exceeding the length of the leaf, and calyx lobes equaling or exceeding the corolla in length. Morphologically, it resembles R. arenicola by having corymbiform inflorescences not exceeding the length of the leaf. However, the two species are easily differentiated by the characters listed in the taxonomic notes of R. arenicola ( Bezerra et al. 2019b) .

Reproductive phenology: —Flowering and fruiting in July.

Distribution and habitat: — Rhynchosia mineira is from the municipality of Couto de Magalhães de Minas in Minas Gerais state, Brazil ( Fig. 11 ). Its occurrence is restricted to only one known location, which is a degraded environment where there is agricultural land and pasture. The species grows in “campo rupestre” (rocky fields) inside the Cerrado domain ( Bezerra et al. 2019b).

Conservation status: —Critically Endangered (CR). According to Bezerra et al. (2019b) the conservation status of R. mineira is assessed as CR, B2a+B2b(iii), based on the criteria and subcriteria of the IUCN Red List ( IUCN 2022).

Figures

FIGURE 11. Geographical distribution of Rhynchosia mantaroensis var. mantaroensis, R. mantaroensis var. cuprinervia, R. melanocarpa and R. mineira in South America.