Rhynchosia platyphylla Benth., Fl. Bras.

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 : 54-55

23. Rhynchosia platyphylla Benth., Fl. Bras. 15(1B): 201. 1862. Type:— BRAZIL, Minas Gerais, s.loc., 1816-1821 (fl.) A. de Saint-Hilaire B1-365 (Lectotype, designated by Grear [1978]: P 00709015 [digital image!]). Iconography: Rodriguésia 70: 13. 2019. ( Fig. 14 D )

Subshrub prostrate, stems simple, pubescent, indumentum light yellow to brownish, with yellow to brownish vesicular glands and sparse bulbous-based trichomes. Stipules 3–8 × 1–2 mm, free, persistent, lanceolate, externally pubescent with yellow vesicular glands and bulbous-based trichomes. Leaves unifoliolate; petiole sessile to subsessile, up to 3mm long; leaflets 5–8.5 × 4.7–9 cm, ovate, elliptical or rounded, surface not bullate, rounded at apex, cordate at base, margin entire, pilose, with yellow vesicular glands on the abaxial surface. Inflorescences axillary, racemose or paniculate, 5.5–10 cm long, many-flowered, equaling or exceeding the length of the subtending leaf; bracts caducous; pedicels 3–6 mm long. Flowers 8.5–12 mm long excluding the pedicel; calyx 9–12 mm long, pilose to pubescent with yellow vesicular glands and bulbous-based trichomes, lobes lanceolate, all of them equaling or exceeding the corolla in length; standard petal 7–10 × 5–6.5 mm, obovate, emarginate to rounded at apex, glabrous, lacking yellow vesicular glands and bulbous-based trichomes, claw 1.5–2 mm long, auricle ca. 0.5 mm long; wing petals 7.8–9 × 1–2 mm, oblong, claw 1–2.3 mm long, auricle ca. 0.5 mm long; keel petals 7.7–8.9 × 2–3.2 mm, falcate, claw 1–3 mm long; stamens 7.5–9.5 mm long; ovary 2.6–3.5 mm long, pubescent, with yellow vesicular glands. Fruits 1.4–2.5 × 0.6–0.8 cm, brown, without constrictions between the seeds, ovate, oblong or elliptical, pubescent, with yellow vesicular glands and bulbous-based trichomes. Seeds 2–3.5 × 1,8– 3 mm, suborbicular, unicolored, brown.

Nomenclatural and taxonomic notes: — Rhynchosia platyphylla was described by Bentham (1862) based on a collection from “Habitat in Brasilia ab A. de St. Hilaire lecta in itinere a Rio de Janeiro ad S. Paulo, loco non indicato”. No St. Hilaire material with this description has been found. Consequently, Grear (1978) designated as a lectotype the collection St. Hilaire 365, deposited in P, noting that Bentham used this material to prepare the description of the species.

Rhynchosia platyphylla is an easily recognizable species because it is the only Rhynchosia in South America which has unifoliolate leaves ( Fig. 14 D ).

Reproductive phenology: — Rhynchosia platyphylla has been collected in flower in January, August, and from October to December; and with fruits in August, November and December.

Distribution and habitat: — Rhynchosia platyphylla is restricted to Brazil, occurring in the midwest and southeast regions ( Fig. 13 ). It occurs in areas of cerrado and in grassy and shrubby fields.

Conservation status: —Least Concern (LC). With an EOO of 288,760 km 2 (GeoCAT, accessed in May 2022), R. platyphylla is assessed as LC. There are many records of this species especially from the Brazilian Midwest. It can occur in ruderal environments such as along roadsides, and it is recorded from some conservation areas (e.g., the Parque Nacional de Brasilia and Chapada dos Guimarães).

Selected Specimens Examined:— BRAZIL. Distrito Federal: Brasília, 0.5 km W de estação de Corpo de Bombeiros em W5N, Asa Norte , 9 December 1983 (fl.), J. H. Kirkbride Jr. 5512 ( UB) ; ibid., estrada Brasilia–Belo Horizonte km 5, 29 November 1976 (fl./fr.), G. Shepherd et al. 3798 ( UEC) ; ibid., immediately E of Lagoa Paraná, 9 December 1965 (fl.), H. S. Irwin et al. 11136 ( NY, UB) ; ibid., Parque Nacional de Brasilia , próximo a área do exército, 07. December 2006 (fl./fr.), J. Roveratti et al. 640 ( UB) ; ibid., margem Córrego Capão Comprido , 29 October 1990 (fl.), P. C. M. Ramos 253 ( UB) ; ibid., Peninsula Norte , 4 December 1983 (fl.), J. A. Ratter & G. C. G. Argent s.n. ( UEC) ; ibid., Reserva Ecológica do IBGE, área de amostragem nº 3 para coleta de material botânico, 18 December 1986 (fl.), M. A. Silva & D. Alvarenga 234 ( SP) ; Planaltina , 8 August 1975 (fl./fr.), E. P. Heringer 15957 ( RB) ; Sobradinho , 10 November 1986 (fl.), E. R. Anjos s.n. ( NY, UB) . Goiás: Estrada Brasília / Belo Horizonte , km 5, 29 November 1976 (fl.), G. Shepherd et al. 344 ( UEC) ; Luziânia , arredores, 4 December 1992 (fl./fr.), G. Hatschbach et al. 58408 ( MBM, NY) . Mato Grosso: Chapada dos Guimarães, Trilha do Atmã, borda Cerrado 15º28’365 S 55º48’293’W, 15 January 2009 (fl.), R. T. Queiroz et al. 1371 ( UEC) . Minas Gerais: Ituitinga, Rodovia Lavras - São João Del Rey, 10 December 1980 (fl./fr.), H. F. Leitão et al. 11898 ( UEC, MBM) .

Figures

FIGURE 13. Geographical distribution of Rhynchosia naineckensis, R. phaseoloides and R. platyphylla in South America.

FIGURE 14. Rhynchosia species. A–C. R. phaseoloides. D. R. platyphylla. E–H. R. reticulata. I–J. R. schomburgkii. K–L. R. senna. (A, E–H, L by L. M. P.A. Bezerra), (B, C, K by T. C. Monteiro), (D by C. Martins) and (I–J by A. P. Fortuna-Perez).