Rhynchosia mantaroensis var. mantaroensis

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 : 40

17.1. Rhynchosia mantaroensis var. mantaroensis . Type:— PERU, Tayacaja , Dep. Huancavelica, “Manto Valley, near la Mejorada”, March 1926 (fl./fr.), A. Weberbauer 7606 (Holotype: F 0043559F [digital image!]; isotypes: BM 000931748 [digital image!], G 00367753 [fragment] [digital image!], G 00367757 [digital image!], GH 00063822 [digital image!], K 000502953 [digital image!], NY 00026949[!], S-R-9726 [digital image!], US 00004685 [digital image!])

Stems puberulous to sericeous, becoming glabrous with age. Stipules 2–4 × 1–1.5 mm, pubescent with yellow vesicular glands. Leaflets 1.7–4.8 × 1.1–2.7 cm, ovate, acute to acuminate at apex, rounded at base, pubescent to villous. Inflorescences 6–10.5 cm long, pedicels 2–4 mm long. Calyx 5–7 cm long, pubescent with yellow and black vesicular glands. Immature fruit 1.4–2.3 × 0.4–6 cm, pubescent to hirsute, with yellow vesicular grands and bulbous-based trichomes.

Nomenclatural and taxonomic notes: — Rhynchosia mantaroensis var. mantaroensis is characterized by its twining stems, inflorescences racemose to paniculate, many-flowered, up to 10.5 cm long. Morphologically, it resembles R. edulis , as both have an oblong fruit with bulbous-based trichomes. However, in R. mantaroensis var. mantaroensis the vesicular glands on the abaxial surface of the leaflets are yellow (vs. vesicular glands on the abaxial surface of the leaflets darker yellow, brown to black in R. edulis ), and the inflorescences are up to 6–10.5 cm long (vs. 7–21 cm long).

Reproductive phenology: —Flowering in March, May and November; fruiting in March, May, June and November.

Distribution and habitat: — Rhynchosia mantaroensis var. mantaroensis occurs in southern Peru ( Fig. 11 ). This taxon can be found in shrubby fields growing in sandy soil.

Conservation status: —Near Threatened (NT). With an EOO of 25,325 km 2 (GeoCAT, accessed in May 2022) this taxon is assessed as NT following the criteria of the IUCN Red List ( IUCN 2022). Efforts to collect more specimens and conserve the species in the wild are needed, since currently there are few records of it and none of them are recent.

Selected Specimens Examined:— PERU. s.loc., 1839-1840 (fl.), M. Cl. Gay s.n. (P 02749565) . Apurimac: Apurimac-valley , s.d (fl./fr.) R. Histch 7654 ( NY) . Cuzco: Anta, Dist. Limatambo, Sauceda , Matorral , 04 June 2004 (fr.), W. Galiano, E. Suclli & A. Rodríguez 6511 ( NY); Paruro, bajando de Agusbamba a Mayhua, March 1938 (fl.), C. Vargas 877 (F V0368662F) . Huancavelica: alrededores de Mejorada , 24 March 1951 (fl.), O. Tovar 289 (US 2100557); ibid., entre Izcuchaca y Mejorada, 2 November 1963 (fl./fr.), O. Tovar 4465 (US 2490538) . Junin: La Mejorada, Mantaro Valley , 23 May 1929 (fl./fr.), E. P. Killip & A. C. Smith 23344 ( NY) .

Figures

FIGURE 11. Geographical distribution of Rhynchosia mantaroensis var. mantaroensis, R. mantaroensis var. cuprinervia, R. melanocarpa and R. mineira in South America.