Rhynchosia calycosa Hemsl., Diagn. Pl.

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 : 18

5. Rhynchosia calycosa Hemsl., Diagn. Pl. Nov. Mexic. 3: 48. 1880.

Dolicholus calycosus (Hemsl.) Standl., Contr. U.S. Natl. Herb. 18(3): 108. 1916. Type :— PANAMA, Chagres, January 1850 (fl./fr.), A. Fendler 72 (Lectotype, first-step designated by Grear [1978]; second-step designated here: K 000502948 [digital image!]; isolectotypes: GH 00063804 [digital image!], K 000502949 [digital image!], MO 125145 [digital image!], US 00004672 [digital image!])

Suffrutescent vine, twining, stems branched, puberulous, indumentum light yellow, with yellow vesicular glands, but lacking bulbous-based trichomes. Stipules 1–2.5 × 1–1.5 mm, free, caducous, lanceolate. Leaves trifoliolate; petiole 1.1–6.8 cm long; leaf rachis 1.1–2 cm long; stipels persistent to falling tardily; leaflets 1.6–7.2 × 1.4–6.7 cm, ovate or deltoid to rhomboid, surface not bullate, acute to acuminate at apex, obtuse to rounded at base, margin entire, puberulous to pilose, with yellow vesicular glands on the abaxial surface. Inflorescences axillary or terminal, racemose or paniculate, 8–27 cm long, many-flowered, exceeding the length of the subtending leaf; bracts caducous; pedicel 1–2 mm long. Flowers 8–10 mm long excluding the pedicel; calyx 9–11 mm long, pubescent to hirsute with yellow vesicular glands but lacking bulbous-based trichomes, lobes lanceolate, all of them equaling or exceeding the corolla in length; standard petal 7–10 × 4–5 mm, orbicular, 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 7–8 × 1.5–2 mm, oblong, claw 1.5–2 mm long, auricle ca. 0.5 mm long; keel petals 8–9 × 2.5–3 mm, falcate, claw 2–2.5 mm long; stamens 8–8.5 mm long; ovary 2–2.5 mm long, pilose, with yellow vesicular glands. Fruits 1.6–2.6 × 0.6–0.8 cm, brown, without constrictions between the seeds, oblong to obovate, glabrescent to puberulous, with sparse yellow vesicular glands, but lacking bulbous-based trichomes. Seeds 3–4 × 3–3.5 mm, reniform, unicolored, dark brown to black.

Nomenclatural and taxonomic notes: — Rhynchosia calycosa was described by Hemsley (1880) based on a Fendler collection from “ Panama: Chagres”, deposited in K. Grear (1978) cited the collection Fendler 72, which has morphological characters matching those given in the species protologue, as the holotype. However, there are two duplicates of this collection at K (K 000502948 and K 000502949), and Grear (1978) did not specify a particular specimen as type. Thus, Grear’s (1978) citation of the specimen at K as the “ holotype ” constitutes the first-step in the lectotypification of the name (see Turland et al. 2018, Art. 9.17). Our designation of the specimen with barcode number K 000502948 constitutes the required second-step.

Rhynchosia calycosa resembles R. reticulata mainly in having its calyx lobes equaling or exceeding the corolla in length and by the shape of the leaflets and fruits. However, R. calycosa differs from R. reticulata by its stipules 1–2.5 × 1–1.5 mm, and caducous (vs. 3–10 × 1–6 mm, persistent to falling late) and by its leaflets puberulous to pilose (vs. pubescent to tomentose).

Reproductive phenology: —Flowering in January, February, April, June and July and fruiting from January to April, June, and July.

Distribution and habitat: — Rhynchosia calycosa occurs in Central America, from Nicaragua to Panama, and in South America, Colombia, Ecuador, and Bolivia ( Fig. 5 ). It can be found along roadsides, secondary vegetation and tropical forests.

Conservation status: —Least Concern (LC). Based on an EOO of 2,836,586 km 2 (GeoCAT, accessed in May 2022), R. calycosa is classified as LC following the criteria of the IUCN Red List ( IUCN 2022). Nevertheless, there are few records of this species for South America and we recommend that efforts to collect and conserve this species are needed, even though it has been temporarily assessed as LC.

Selected Specimens Examined:— BOLIVIA. Santa Cruz: Velasco, Campamento El Refugio a 7 km al E de la casa, yendo hacia la serrania Caparuch , 9 July 1994 (fr.), R. Guillén & S. Coria 2144 ( NY) . COLOMBIA. Bolivar: Morales, On Rio Sinu , 05 February 1918 (fl.), F. W. Pennell 4161 ( NY) . Magdalena: Sevilla, Carretera Santa Maria— Fundación , en la ofilla del río, 30 April 1981 (fl./fr.), R. Barneby 82 ( NY) . COSTA RICA. Puntarenas: Tropical rain forest and moist secondary forest on El General Valley , vicinity of San Isidoro El General, 11 March 1966 (fr.), R. A. Molina 18185 (US digital image) . ECUADOR. El Oro: Guarumo , December 1875 (fl.), André 500 ( NY) ; Guayas, Guayaquil , 18 June 1923 (fl./fr.), A. S. Hitchcock 20146 ( NY) . Manabi: Caraquez, 23 June 1926 (fl./fr.), H. E. Anthony & G. H. F. Tate 92 (US digital image); Roadside at Naranja, north of Pajan , 17 July 1942 (fl./fr.), O. L. Haught 3407 ( NY) . NICARAGUA. Chontales: Acoyapa, 2 km south of Acoyapa , 04 January 1969 (fl.), C. E. Nichols 1735 ( MEXU 1188769 ) . PANAMA. Agricultural Experiment Station at Matias Hernandez, January 1915 (fl./fr.), H. F. Pittier 6911 (US digital image); Ancon, Canal Zone , 24 December 1912 (fl.), B. Celestine 69 (US digital image) ; Colón, Vicinity of Gatuncillo, Canal Zone , 26 February 1923 (fr.), C. V. Piper 5619 (US digital image) ; Darien, 13 February 1967 (fr.), J. A. Duke 10105 (US digital image); Río Tocumen , 03 January 1924 (fl./fr.), P. C. Standley 29449 (US digital image) .

Figures

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