Rhynchosia leucophylla (Benth.) 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 : 35-36

14. Rhynchosia leucophylla (Benth.) Benth., Fl. Bras. 15(1B): 202. 1862

Basionym: — Arcyphyllum leucophyllum Benth., Linnaea 22: 525. 1849. Type: BRAZIL, “In Prov. São Paulo ” s.d. (fr.), Riedel 443 (Lectotype, designated by Grear [1978]: K 000502960 [digital image!]). Iconography: Rodriguésia 70: 9. 2019 .

Rhynchosia leucophylla fo. elliptica Chodat & Hassl. Bull. Herb. Boissier , sér. 2. 4(9): 903. 1904. Type : PARAGUAY, “in campo pr. Igatimi”, December 1898 -99, (fl./fr.), E. Hassler 5620 (Lectotype, first-step designated by Grear [1978]; second-step designated here: G 00400122 [digital image!]; isolectotypes: BM 000538510 [digital image!]; G 00400158 [digital image!]; G 00400159 [digital image!]; K 000502958 [digital image!]; NY 00026947[!]; P 00708609 [digital image!], P 00708610 [digital image!]; UC 950971 [digital image!]) .

Rhynchosia leucophylla fo. pubescens Chodat & Hassl. Bull. Herb. Boissier, sér. 2. 4(9): 903. 1904. Type : PARAGUAY, “in campis pr. Igatimi”, December 1898 -99, (fl./fr.), E. Hassler 5621 (Lectotype, first-step designated by Grear [1978]; second-step designated here: G 00400157 [digital image!]; isolectotypes: BM 000538511 [digital image!]; G 00400156 [digital image!]; K 000502959 [digital image!]; NY 00026948[!]; P 00708611 [digital image!]) .

Rhynchosia leucophylla fo. laxifolia Chodat & Hassl. Bull. Herb. Boissier, sér. 2. 4(9): 903. 1904. Type : PARAGUAY, “in campis pr. flumen Jejui Guazu”, December 1898 -99, E. Hassler 5725 (Holotype: G [not seen]) .

S ubshrub erect, stems simple to branched, densely pubescent, indumentum cinereous, with sparse yellow vesicular glands, but lacking bulbous-based trichomes. Stipules 2–3.8 × 1.5–3 mm, free, caducous, lanceolate, externally pubescent with yellow vesicular glands, but lacking bulbous-based trichomes. Leaves trifoliolate; sessile to subsessile, petioles up to 5mm long; leaf rachis 0.4–0.8 cm long; stipels absent; leaflets 2.5–7.2 × 1.3–5.6 cm, ovate, elliptical, obovate, oblong or rounded, surface not bullate, obtuse to rounded at apex, cuneate to obtuse at base, margin entire, pubescent to tomentose, with sparse yellow vesicular glands on the abaxial surface. Inflorescences terminal or axillary, racemose, 4.3–15.6 cm long, many-flowered, equaling or exceeding the length of the subtending leaf; bracts caducous; pedicel 2–5 mm long. Flowers 8–11 mm long excluding the pedicel; calyx 8–13 mm long, pubescent with yellow vesicular glands and bulbous-based trichomes, lobes lanceolate, all of them equaling or exceeding the corolla in length; standard petal 8–9 × 4–5 mm, oblong to obovate, retuse to rounded at apex, glabrous, lacking vesicular glands and bulbous-based trichomes, claw 1.5–2 mm long, auricle ca. 0.5 mm long; wing petals 7,5–9 × 1–1.5 mm, oblong, claw 2.5–3 mm long, auricle 0.5–1 mm long; keel petals 8–9.5 × 1.5–2 mm, falcate, claw 2.5–3 mm long; stamens 9–11 mm long; ovary 3.5–4 mm long, pubescent, with a few yellow vesicular glands. Fruits 1.2–1.7 × 0.5–0.6 cm, cinereous, without constrictions between the seeds, elliptical or oblong, densely pubescent, with a few yellow vesicular glands, but lacking bulbous-based trichomes. Seeds 3–4 × 2–3 mm, suborbicular, unicolored, brown to black.

Nomenclatural and taxonomic notes: — Grear (1978) cited the collection Hassler 5620 at G as the lectotype of R. leucophylla fo. elliptica. As there are three duplicates of this collection number in the G herbarium (G 00400122; G 00400158; G 00400159) and the author did not specify a particular specimen as type, the designation of Grear (1978) should be treated as the first-step lectotypification. Thus, our designation of the specimen with barcode number G 00400122 constitutes the required second-step lectotype of R. leucophylla fo. elliptica (see Turland et al. 2018, Art. 9.17). A similar situation is noted for R. leucophylla fo. pubescens. There are two duplicates of the gathering Hassler 5621 at G (00400157; 00400156) and Grear (1978) did not designate a particular one as type. Therefore, the specimen with barcode number G 00400157 is here designated as a second-step lectotypification of R. leucophylla fo. pubescens.

Although we analysed collections of many herbaria, we were unable to see the type material of R. leucophylla fo. laxifolia in G. Since we have been informed by the curator that some materials of the genus were sent on loan but have not been returned, we retain this taxon as a synonym of R. leucophylla based on the characters presented in the taxon protologue.

Rhynchosia leucophylla is polymorphic with respect to leaflet shape, which can be ovate, elliptical, obovate, oblong, or rounded. Notwithstanding, the species is easily recognizable by its erect subshrub habit, the presence of a cinereous indumentum on the whole plant, the sessile to subsessile leaves, glabrous corollas and calyx lobes equaling or exceeding the corolla in length.

Reproductive phenology: —Flowering from January to March and in May, July, November and December; fruiting from January to May and in November.

Distribution and habitat: — Rhynchosia leucophylla occurs in Brazil and Paraguay ( Fig. 9 ) in areas of the Cerrado domain, in shrubby fields, pastures and along roadsides.

Conservation status: — Least Concern ( LC). Based on an EOO of 231,220 km 2 (GeoCAT, accessed in May 2022), R. leucophylla is classified as LC following IUCN Red List criteria ( IUCN 2022). The species is commonly found in Mato Grosso do Sul state, Brazil .

Selected Specimens Examined:— BRAZIL. Mato Grosso do Sul: Amambaí, arredores da tribo Caiuá, 1979 (fr.), W. G. Garcia 13875 ( UEC) ; Bela Vista, lado direito da BR 267 (sentido Porto Murtinho ), 26 April 2012 (fr.), W. Vargas et al. 10 ( MBM) ; ibid., Rod. BR-267, próximo do trevo para Bela Vista , 11 March 2003 (fl./fr.), G. Hatschbach et al. 74572 ( MBM) ; Bonito, Rodovia Bonito, Campo dos Índios, próximo do Córrego Três Morros , 8 November 2002 (fl.), G. Hatschbach et al. 73906 ( MBM) ; ibid., 10 March 2003 (fr.), G. Hatschbach 74468 ( MBM) ; ibid., Rod. MS-270, km 15-20, 21 May 2002 (fl./fr.), G. Hatschbach et al. 73242 ( MBM) ; Dourados, Rio Dourado , 16 May 1976 (fl./fr.), G. Hatschbach 38687 ( MBM, NY) ; Maracajú , 03 February 1952 (fl./fr.), E. Kuhlmann s.n. ( SP) ; Rio Brilhante, Entroncamento , 16 February 1970 (fl./fr.), G. Hatschbach 23623 ( MBM) ; Sidrolândia, Santa Fé , 23 January 1971 (fl./ fr.), G. Hatschbach 25055 ( MBM) . São Paulo: Capão Bonito, mais ou menos no km 14 da rodovia Bonito-Itapeva , 09 December 1966 (fl.), J. Mattos & N. Mattos 14871 ( SP) ; ibid., Parque Florestal Getulio Vargas , 14 November 1967 (fl./ fr.), J. Mattos & N. Mattos 15127 ( NY, SP) . PARAGUAY. Amambay: Colonia Estrella , 45 km NW de P. J. Caballero, 8 December 1997 (fl./fr.), A. Schinini & M. Dematteis 33558 ( NY) ; Pedro Juan Caballero, Fazenda Cerro-Cora , 15 November 1964 (fl.), J. C. Gomes 1593 ( SP) ; Sierra de Amambay , 27 July 1910 (fl.), E. Hassler 9783 (P) . Caaguazú: Campo 9, cercado arenoso, 20 February 1982 (fl./fr.), J. F. Casas & J. Molero 6348 ( NY) ; East of Caaguazú , 28 December 1994 (fl.), E. M. Zardini & L. Guerrero 42081 ( NY) .

Figures

FIGURE 9. Geographical distribution of Rhynchosia hauthalii, R. lateritia, R. leucophylla and R. lineata in South America.