Rhynchosia claussenii 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 : 19

6. Rhynchosia claussenii Benth., Fl. Bras. 15(1B): 201. 1862.

Arcyphyllum capitatum Benth. Linnaea 22: 525. 1849. Type:— BRAZIL, Minas Gerais, “ Caxoeiras do Campo ” s.d. (fl./fr.), P. Claussen 172 (Lectotype, designated by Grear [1978]: K 000502965 [digital image!]; isolectotypes: F 1539658 [digital image!], G 00367747 [digital image!], K 000502966, 000502967 [digital image!]). Iconography: Rodriguésia 70: 5. 2019. ( Fig. 2 F )

Subshrub erect, stems simple to few-branched, indumentum hirsute, yellow, with yellow vesicular glands, but lacking bulbous-based trichomes. Stipules 4–12 × 1.5–4 mm, free, persistent, ovate, lanceolate or elliptical, externally hirsute with yellow to light brown vesicular glands, but lacking bulbous-based trichomes. Leaves trifoliolate; petiole 3.1–6.2 cm long; leaf rachis 0.9–1.5 cm long; stipels falling late; leaflets 2.1–5.8 × 1.2–4.7 cm, ovate, elliptical, oblong or rounded, surface not bullate, mucronate, retuse or cuneate to rounded at apex, rounded at base, margin entire, pilose to hirsute, with yellow to light brown vesicular glands on both surfaces. Inflorescences axillary or terminal, corymbiform, 2.1–7.4 cm long, many-flowered, not exceeding the length of the subtending leaf; bracts caducous; pedicel 2–5.5 mm long. Flowers 9–17 mm long excluding the pedicel; calyx 8–16 mm long, hirsute, with yellow vesicular glands, but lacking bulbous-based trichomes, lobes elliptical or narrowly ovate, all of them equaling or exceeding the corolla in length; standard petal 7–10 × 4–6 mm, obovate, rounded at apex, glabrous, with yellow vesicular glands, 1.5–2 mm long, auricle 0.4–0.5 mm long; wing petals 7–10 × 1–2 mm, oblong, claw 1.8–2 mm long, auricle 0.6–1 mm long; keel petals 8–11 × 2–4 mm, falcate, claw 2–2.3 mm long; stamens 8–11 mm long; ovary 2–3 mm long, hairy, with yellow vesicular glands. Fruits 1.1–2 × 0.5–0.6 cm, brownish, without constrictions between the seeds, ovate or oblong, pilose to hirsute, with yellow vesicular glands, but lacking bulbous-based trichomes. Seeds 2–3 × 2–2.5 mm, suborbicular, unicolored, brown to black.

Nomenclatural and taxonomic notes: — Rhynchosia claussenii was first described by Bentham (1849) as Arcyphyllum capitatum . The binomial Rhynchosia capitata had already been assigned to a different species, so Bentham (1862) established the name Rhynchosia claussenii in honor of Claussen, who gathered the type collection.

In the protologue of R. claussenii two collections were mentioned: “Habitat in prov. Minarum, ad Caxoeira do Campo: Claussen” and “in campis siccis inter Goyaz et Cuiaba: Weddell”.According to Grear (1978), the type specimen at K consists of these two different collections of R. claussenii (the two being syntypes). The Claussen collection was designated as a lectotype by Grear (1978), and the collection of Weddell is considered remaining syntype.

Rhynchosia claussenii can be easily recognized by its erect shrubby habit ( Fig. 2 F ); the hirsute indumentum of the whole plant; the corymbiform inflorescence not exceeding the length of the subtending leaf; well-developed elliptical or narrowly ovate calyx lobes; and by the glabrous corolla ( Bezerra et al. 2019a).

Reproductive phenology: —Flowering from February to March and October to December; fruiting in February to March, August, and from October to December.

Distribution and habitat: — Rhynchosia claussenii occurs in Cerrado, campos rupestres (rocky fields) and in sandy soil areas of the midwest, northeast and southeast regions of Brazil and the northeast region of Paraguay ( Fig. 5 ).

Conservation status: — Least Concern ( LC). Based on an EOO of 1,961,736 km 2 (GeoCAT, accessed in May 2022), R. claussenii is classified as LC following IUCN Red List criteria ( IUCN 2022). The species was recently collected in Parque Nacional de Brasília , DF, Brazil (C. R. Martins 2431) .

Selected Specimens Examined:— BRAZIL. Ceará: Guaraciaba do Norte, Chapada da Ibiapaba , 10 April 1992 (fl.), A. Fernandes et al. s.n. ( EAC) . Distrito Federal: Brasília, Parque Nacional de Brasília , 21 February 2004 (fl./ fr.), C. R. Martins 252 ( UEC) ; ibid., 18 December 2016 (fr.), C. R. Martins 2431 ( CEN) . Goiás: Anápolis , margem da Rodovia Brasilia-Anapolis, 16 December 1965 (fl./fr.), R. P. Belém 2025 ( IPA) ; Aparecida de Goiania, Chácara Jatobá , 26 December 2002 (fr.), J. F. B. Pastore 198 ( CEN) ; Corumbá de Goiás , 15 km. S of Corumbá de Goiás, elevation 1000m, 30 November 1965 (fl.), H. S. Irwin et al. s/n ( UB) ; Estrada Brasília / Belo Horizonte , km 5, 29 November 1976 (fr.), G. Shepherd et al. 3799 ( UEC) ; “in campis siccis inter Goyaz et Cuiaba”, October 1844 (fl.) Weddell 2962 (K); Luziânia, BR-30, a 5 km divisa Cristalina - GO, 20 November 1976 (fl.), A. Allem 462 ( RB, CEN) . Maranhão: Balsas, Morro Larerita , 23 March 1997 (fl./fr.), R. C. Oliveira et al. 717 ( UEC) . Mato Grosso: Cuiabá, 8 km SE Cuiabá, caminho para Faz. Roselândia , 30 September 1986 (fl.), A.M. de Carvalho 2155 ( CEPEC) . Mato Grosso do Sul: Camapuã , 08 February 1974 (fr.), G. Hatschbach 33932 ( MBM) ; Campo Grande, BR-163, próximo a Água Ruim , 14 July 1970 (fr.), G. Hatschbach & O. Guimarães 24636 ( MBM) . Minas Gerais: Morrinhos , 24 November 1975 (fl.), G. Hatschbach 37824 ( MBM) ; Paraopeba, Horto Florestal , 20 October 1954 (fl./fr.), E. P. Heringer 3596 ( UB) . São Paulo: Mogi Guaçu, Reserva Florestal, Fazenda Campininha , 30 October 1957 (fl.), M. Kuhlmann 4260 ( SP) . PARAGUAY. Caaguazú, Sierra de Maracayú “in altoplanitie et decliviis”, s.d. (fl./fr.), E. Hassler 5315 (P) .

Figures

FIGURE 2. Rhynchosia species. A–C. R. arenicola. D, E. R. balansae. F. R. claussenii. G–J. R. corylifolia. (A–C, G–J by T.C. Monteiro); (D, E by R. Ripley) and (F. by C. Martins).

FIGURE 5. Geographical distribution of Rhynchosia calycosa, R. claussenii and R. corylifolia in South America.