Rhynchosia schomburgkii 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 : 59-61

26. Rhynchosia schomburgkii Benth., Fl. Bras. 15(1B): 203. 1862. Type : — GUYANA, “Sides of dry savannahs”, 1839 (fl.), Robert Schomburgk [ser. 1] 653 (Lectotype, first-step designated by Grear [1978]; second-step designated here: K 000502978 [digital image!]; isolectotypes: BM000931745 [digital image!]; G [not seen]; K 000502977 [digital image!], K 000502979 [digital image!]; P00709026 00709027 [digital image!]). Iconography: Rodriguésia 70: 17. 2019. ( Fig. 14 I–J )

Dolicholus pittieri Standl., Contr. U.S. Natl. Herb. 17(5): 433. 1914. Rhynchosia pittieri (Standl.) Standl., Publ. Field Mus. Nat. Hist. , Bot. Ser. 4(8): 214. 1929. Type: COLOMBIA, “Around Cali western Cauca Valley”, XII.1905 (fl./fr.) H. Pittier 688 (Holotype: US 530856 [digital image!] ; isotype: US 1059965 [digital image!] ).

Rhynchosia caliensis Harms, Notizbl. Bot. Gart. Berlin-Dahlem 11: 783. 1933. Type: COLOMBIA, Cali , 1000-1200m, 20.V.1883, (fl./ fr.) F. C. Lehmann 2861 (Lectotype, designated by Grear 1978: K 000502950 [digital image!]; isolectotype: US 01107536 [digital image!]) .

Subshrub erect to twining, stems branched, pubescent, indumentum white to light yellow, with yellow vesicular glands and bulbous-based trichomes. Stipules 5–13 × 1–4 mm, free, caducous, lanceolate, externally pubescent with yellow vesicular glands and bulbous-based trichomes. Leaves trifoliolate; petiole 2.1–5.1 cm long; leaf rachis 0.8–1.9 cm long; stipels persistent; leaflets 3.2–7 × 1.9–5 cm, ovate or elliptical, surface not bullate, attenuate to cuneate at apex, cuneate to rounded at base, margin entire, pilose to pubescent, with yellow vesicular glands on both surfaces. Inflorescences axillary, paniculate or rarely racemose, 6–22 cm long, many-flowered, exceeding the length of the subtending leaf; bracts caducous; pedicels 4.5–6 mm long. Flowers 13–18 mm long excluding the pedicel; calyx 8.5– 17 mm long, pubescent, with yellow vesicular glands and bulbous-based trichomes, lobes lanceolate, only the ventral lobe exceeding the corolla in length; standard petal 11–18 × 6–11 mm, obovate, emarginate at apex, glabrous, without yellow vesicular glands and bulbous-based trichomes, claw 3–4 mm long, auricle ca. 0.5 mm long; wing petals 11–14 × 1–3 mm, oblong, claw 2.5–4.5 mm long, auricle ca. 0.5 mm long; keel petals 11–15 × 4–5 mm, falcate, claw 4–4.5 mm long; stamens 14–18 mm long; ovary 2.5–4 mm long, pubescent, with yellow vesicular glands. Fruits 1.6–3.5 × 07– 10 mm, brown, without constrictions between the seeds, oblong, pubescent, with yellow vesicular glands and bulbous-based trichomes. Seeds 4–5.5 × 3.5–4.5 mm, ovate or reniform, unicolored, brown to black.

Nomenclatural and taxonomic notes: — Bentham (1862) described R. schomburgkii in a short description, comparing it with R. reticulata . As he did not provide any information about the type species in the protologue, Grear (1978) lecotypified the species with Schomburgk 653 housed in K, assuming that Bentham must have used this collection to describe R. schomburgkii (see Turland et al. 2018, Art. 9.4). However, there are three duplicates of Schomburgk 653 in K (K 000502978, K 000502977 and K000502979) and Grear (1978) did not specify a particular one as the lectotype. Therefore, Grear`s citation of the specimen at K should be treated as the first-step lectotypification (see Turland et al. 2018, Art. 9.17) and our designation of the specimen with barcode number K 000502978 constitutes the required second-step of R. schomburgkii .

Rhynchosia schomburgkii is an easily recognizable species, especially in having only the ventral calyx lobe exceeding the corolla in length ( Fig. 14 I ). It is also characterized by its twining stems ( Fig. 14 J ), stipules 5–13 × 1–4 mm, its axillary inflorescences often paniculate, and by a glabrous corolla.

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

Distribution and habitat: — Rhynchosia schomburgkii is a species restricted to South America. It occurs in northern Brazil, Colombia, Guyana, and Venezuela ( Fig. 15 ). It is reported from savannas, humid forests, along roadsides and pastures.

Conservation status: —Least Concern (LC). With an EOO of 1,423,755 km 2 (GeoCAT, accessed in May 2022), R. schomburgkii is assessed as LC based on the criteria of the IUCN Red List ( IUCN 2022).

Selected Specimens Examined:— BRAZIL. Roraima: 5 km S of Ilha de Maraca on the road to the Ecological Station on the SE end of the island, 9 October 1987 (fl./fr.), J. Pruski et al. 3437 ( INPA, NY) ; 27 km de Boa Vista em direção a Bonfim, BR 401, 18 July 2006 (fl.), A. S. Flores et al. 1104 ( RB) ; 65 km NW of Boa Vista, within a radius of 15 km from the vilage of Taiano , along roads and in agricultural fields, 11 October 1977 (fr.), L. Coradin & M. R. Cordeiro 605 ( INPA, NY) ; Alto Alegre , BR 205 03º01’39.3’’N 61º16’17.5’’ W., 9 September 2009 (fl./fr.), A. S. Flores et al. 2357 ( RB) ; ibid., Ilha de Maracá , estação, 12 March 1987 (fl.), G. P. Lewis 1487 ( INPA) ; Boa vista, along Boa Vista, Bonfim road, BR 401, KM 40, 15 October 1977 (fr.), L. Coradin & M. R. Cordeiro 703 ( INPA, NY) ; ibid., Reserva Ecológica de Maracá , 12 October 1987 (fr.), G. P. Lewis 1656 ( NY) ; Estrada Boa Vista— Venezuela, Rio Surumu , 1 December 1977 (fl.), W. C. Steward et al. 163 ( INPA, NY) ; Normandia, Fazenda Alvorada, 08 October 1995 (fl./fr.), I. S. Miranda 965 (INPASerra da Lua , 12 January 1969 (fl.), G. T. Prance et al. 9203 ( INPA, NY) . COLOMBIA. Antioquia: Gomes Plata , 10-15 km en la vía Barbosa-Porce-Amalfi, N de Barbosa, 04 December 1989 (fl./fr.), R. Callejas, O. Betancur & O. D. Escobar 8928 ( NY) ; Medellín , 15 October 1927 (fl.), R. A. Toro 751 ( NY) ; San Jeronimo, km 10 of road San Jeronimo-Medellín , 19 September 1987 (fl.), J. L. Zarucchi et al. 5437 ( NY) . Valle del Cauca: Buga , “El Vinculo”, government owned regenerating forest about 20 years old, 14 July 1982 (fl./fr.), H. Murphy 675 ( NY) ; Carretera Popayán a Pasto , entre El Bordo (Cauca) y La Unión (Nariño) , 24 July 1948 (fl./fr.), H. Garcia-Barriga, J. G. Hawkes & M Villareal 13004 ( NY) ; Protedillo to Miraflores Palmira , 27 May 1922 (fr.), F. W. Pennel & E. P Killip 6011a ( NY) ; Yumbo , 20 May 1922 (fl./fr.), F. W. Pennel 5853 ( NY) . GUYANA. Kanuku Montains , 16 February 1985 (fl.), M. J. Jansen-Jacobs et al. 269 ( NY) . Rupununi: N of Shea, Camp 1, 19 Janury 1994 (fl./fr.), M. J. Jansen-Jacobs et al. 3268 (P); St. Ignatius , July 1958 (fl.), S. G. Harrisa 1333 ( NY) ; Stand 7 SE of Kumu Creek, 14-15 August 1963 (fl./fr.), R. Goodland & P. F. Maycock 423 ( NY) ; Stand 11, Makushi area , 21 August 1963 (fr.), R. Goodland & P. F. Maycock 506 ( NY) ; Potaro-Siparuni: Pakaraima Mountains, Upper Ireng River, E bank adjacent to Cipo settlement, 5 July 1994 (fl.), T. W. Henkel 5460 ( NY) ; Trail from Kato to Paramakatoi , 12 March 1989 (fl.), W. Hahn 5631 ( INPA, NY) . VENEZUELA. As proximidades da divisa com o Brasil , km 3 a 9, morro com 1200m de altitude, 27 September 1979 (fl.), N. A. Rosa & O. C. Nascimento 3569 ( INPA, NY) ; Bolívar: Represa Guri , 30 to 40 km E of Ciudad Piar by winding road, 7-8 April 1981 (fl./fr.), R. Liesner & A. González 11387 ( NY) ; Roscio , 23 June 1981 (fl.), E. Rutkis 333 ( NY) ; Santa Elena de Uairén , campo natural de terra firme, floresta nos arredores, 05 September 1979 (fl./fr.), N. A. Rosa & O. C. Nascimento 3312 ( INPA, NY) ; Sifontes, Sabana 6 km al NE de Tumereno, March 1986 (fl.), A. Fernandez 2718 ( INPA, NY) ; Vicinity of camp, 5 km from Hato de Nuria, E of Miamo , Altiplanice de Nuria , alt 400m, 12 January 1961 (fl.), J. A. Steyermark 88376 ( NY) . Merida: Calzeta de la Botella, 14 April 1957 (fl./fr.), A. L. Bernardi 6521 ( NY) .

Figures

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).

FIGURE 15. Geographical distribution of Rhynchosia reticulata, R. rojasii, R. schomburgkii and R. senna in South America.