1. Adesmia bicolor (Poir.) DC., Ann. Sci. Nat. (Paris) 4: 95 (1825a).

Type:— URUGUAY. Montevideo, 1767, {fl./fr.}, Commerson, P. s.n. (holotype: P barcode P 00678651 [photo!], isotype: P barcode P 02297855 [photo!]) .

≡ Hedysarum bicolorum Poir., Encycl. [J. Lamarck et al.] 6(2): 448 (1805).

≡ Patagonium bicolor (Poir.) Kuntze, Revis. Gen. Pl. 1: 200 (1891).

= Adesmia pendula (Poir.) DC., Ann. Sci. Nat. (Paris) 4: 95 (1825a).

Type:— URUGUAY. Montevideo, 1767, {fl./fr.}. Commerson, P. s.n. (holotype: P barcode P 00678650 [photo!], isotypes: P barcode P 02297854 [photo!], P barcode P 02297853 [photo!], SI barcode SI 003897 [fragment, photo!]) .

≡ Hedysarum pendulum Poir., Encycl. [J. Lamarck et al.] 6(2): 449 (1805).

≡ Patagonium pendulum (Poir.) Macloskie, Rep. Princeton Univ. Exped. Patagonia, Botany 8(2): 518 (1905).

= Adesmia glabriuscula Vogel, Linnaea 10: 592 (1836).

Type:— CHILE. Region VIII [Bío-Bío]: Talcaguano, s.d., {fl./fr.}. Philippi, F. s.n. (holotype: B [presumed destroyed], negative of the holotype F barcode F 0 BN 002190 [photo!]). BRAZIL. Rio Grande do Sul: Uruguaiana, Campus da PUC –Uruguaiana (RS), potreiro de divisa Estação Experimental IPZFO, 25 September 1986, {fl./fr.}, Galvani, F. R. 665 (neotype, designated here: UEC barcode UEC 103483!, isoneotypes HUCS barcode HUCS 2690!; MPUC barcode MPUC 22296!) .

≡ Patagonium glabriusculum (Vogel) Kuntze, Revis. Gen. Pl. 1: 200 (1891).

= Adesmia radicans Clos, Fl. Chil. [Gay] 2(2): 173 (1847).

Type:— CHILE. Region V [Valparaíso]: Quillota, Santiago, 1829, {fl./fr.}. Bertero, C. L. G. 767 (first step lectotype designated in Ulibarri and Burkart 38: 68 (2000): P, second step lectotype, designated here: P barcode P02297857 [photo!], isolectotypes HAL 0119480; L 1970583 [photo!]; L1929961 [photo!]; M barcode M0010742; MO2481457; NY4964; P barcode P02297859 [photo!], P barcode P02297858 [photo!], P barcode P03570136 [photo!], P barcode P02297856 [photo!]; SI004132 [fragment, photo!], SI004133 [photo!]; negative of the isolectotype F 27917 [photo!]) .

≡ Patagonium radicans (Clos) Kuntze, Revis. Gen. Pl. 1: 200 (1891).

= Adesmia radicans Bertero ex Steud., Nomenclator Botanicus. Editio secunda 1(1–2): 27 (1840). nom. nud.

Prostrate subshrubs with adventitious roots from stem branch nodes. Stem glabrescent to glabrous, sometimes with a sparce indumentum of white tector hairs on all green plant parts intermixed with short ochraceous glandular setules on the inflorescence, bracts, pedicels, and calyces. Stipules 2–6× 0.5–3.5 mm, lanceolate to deltate, glabrescent to glabrous. Leaves with (5–)7–10(–12) pairs of leaflets; petiole 0.7–12.5 cm long, rachis 1–9 cm long, glabrescent to glabrous; leaflets 2–16× 1–5.5 mm, elliptic to oboVate, apex retuse to obtuse, base acute to rounded, margin entire, glabrescent to glabrous on both surfaces. Raceme axillary or terminal, 3–40 cm long, glabrescent; bracts 1.5–5 mm long, deltate to lanceolate, pubescent to glabrescent; pedicel 2–40 mm long, glabrescent to glabrous. Flowers 9–15 mm long; calyx 4.5–9 mm long, externally glabrescent to glabrous, internally hirsute on the lobes; lobes 1–3.8 mm long, narrowly-triangular to deltate; standard petal 8–14× 6.5–11.5 mm, orbicular, apex emarginate to obtuse, externallY glabrescent to glabrous; claw 4–7.5× 1–3 mm, internallY pubescent; wing petals 8.5–13× 3–5 mm, oboVate to wide-oboVate, claw 4–6 mm long; keel petals 7–10× 2.5–3.5 mm, falcate, claw 3.5–5.5 mm long; stamens 7–10 mm long, anthers elliptical to orbicular; gynoecium 9–13 mm long; ovary 4–6 mm long, pubescent, 5–7(–9)-ovulate. Hemicraspedium 15–20 mm long, straight to curved, light to dark brownish, pubescent to glabrescent, with abundant short ochraceous glandular setules, fruit with 3–6 articles, these 2.5–3.6× 2.5–4 mm, lenticular. Seeds brownish to black, 1.5–2.5× 1.5–2.5 mm, without an aril, orbicular. (Figures 2, 3, and 4).

Distribution and Habitat —The species occurs extensively throughout southern South America, in Rio Grande do Sul state (Brazil), and in Uruguay (Fig. 5). It also occurs in Argentina, frequently in northeast Buenos Aires province, and it is also found in Corrientes, Entre Ríos, Santa Fé, Cordoba, Tucuman, San Luis, and Rio Negro (Burkart 1966), and in the central provinces of Chile, including Bíobío and Valparaíso. Adesmia bicolor occurs in open grasslands (Fig. 6), flooded grasslands, pastures, and along riverbanks.

Phenology —Found with flowers from September to January and with fruits from November to February.

Conservation status —Least Concern (LC). Adesmia bicolor is one of the best sampled species of series Adesmia in herbaria and presents one of the largest extents of occurrence of all the species of the series (EOO: 1.275.584,03 km²). It also has an area of occupancy (AOO) of 160 km ² and was recently collected inside protected areas (Fig. 6) in Rio Grande do Sul state. Thus, the species does not qualify for a category of threat following the criteria established by IUCN (IUCN 2019).

Etymology —The epithet bicolor refers to the color of the flowers, which have the standard petal exterior reddish and the interior yellow with red nectar veins.

Notes — Adesmia bicolor is distinguished from other species of the series Adesmia by its lenticular fruit articles, with an indumentum of short glandular hairs (Figs. 2 and 4) (vs. orbicular articles with a sparse glandular indumentum in A. globosa). The leaves of A. bicolor vary in size from 4 to 20 cm long, perhaps partly due to the pressures of pasture farming; the species is known as a forage species in natural grasslands (Araújo 1940; Burkart 1966; Miotto and Leitão Filho 1993).

Poiret (1804) described Adesmia bicolor and A. pendula based on samples from the Jussieu Herbarium, collected by Commerson in Montevideo. In the protologue of Adesmia pendula, Poiret (1804) mentions that the species can be diagnosed by its pendant fruits on long pedicels. However, its fruits and pedicels have the same shape and indumentum as A. bicolor, and there are no other features that differentiate the two taxa. This evident morphological similarity led us to consider A. pendula as a synonym of A. bicolor, following Burkart (1966), Miotto and Leitão Filho (1993), Davyt and Izaguirre (1996), and Ulibarri and Burkart (2000). In 1857, the collections of the Jussieu Herbarium were donated to the Paris Herbarium (P), which already housed specimens collected by Commerson in Montevideo, here considered as isotypes. The holotype material of A. bicolor and A. pendula both have a label of the Jussieu Herbarium, nº15634 (P00678651) and nº15633 (P02297854), respectively. Poiret (1804) also described A. pendula Var. β, not mentioned by Burkart (1966). This variety differs from the typical variety by the incanous indumentum and corresponds to A. incana Vogel.

When describing Adesmia glabriuscula, Vogel (1836) cited only Chile as the type locality. In the Field Museum (F) collection of Berlin (B) negatives, there is a negative identified as A. glabriuscula from Talcaguano, Chile (F 2190) with a label citing Vogel’s protologue of the species. The negative shows the same distinctive lenticular fruit articles of A. bicolor, as noted by Burkart (1966) who synonymized A. glabriuscula under A. bicolor . As the Berlin material is presumed destroyed during World War II, a neotype is proposed here. We could not find any samples from Chile (other than the type collection of A. radicans) that matches A. bicolor and A. glabriuscula, so we assigned a neotype from Brazil that matches the long leaves of A. glabriuscula type material, as well as matching Vogel’s original description of the taxon.

Steudel (1840) cited Adesmia radicans Bert. as an accepted name and A. glabriuscula as its synonym, but Bertero never validly published A. radicans . Clos (1846) formally described A. radicans and cited Quillota in Chile as the type locality, probably referring to the collection of C.L.G. Bertero767 from Quillota, that has duplicate specimens in HAL, L, M, MO, NY, P, and SI. In 1958, Burkart chose specimen P02297857 as a lectotype but did not validly publish that designation (he only placed a lectotype label on the specimen). Later, Ulibarri and Burkart (2000) considered as a holotype a specimen in the Paris Herbarium (P). However, Ulibarri and Burkart had, in fact, made a first step lectotypification, because P houses five duplicates of the Bertero 767 collection. Thus, following article 9.17 of the Shenzen code (Turland et al. 2018) here we designate P02297857 as the second step lectotype, as this specimen bears mature fruits, which best fits the description in the protologue. Adesmia radicans has lenticular fruit articles and is considered as a synonym of A. bicolor in agreement with previous studies (Burkart 1966; Miotto and Leitão Filho 1993; Davyt and Izaguirre 1996, Ulibarri and Burkart 2000).

Additional Specimens Examined — ARGENTINA. BUENOS AIRES: Magdalena, 04 November 1957, Vervoorst, F. s.n. (L 1929959 [photo!]). Ranchos, camino a G. Belgrano, 5 km S, 17 January 1957, Vervoorst, F. s/n (L 1929960 [photo!]). CORRIENTES: Bella Vista, 13 September 1972, A. Schinini 5276 (MBM 031386). Goya, Batelito (ruta 126), 08 November 1972, L. A. Mroginski 22708 (RB 250927). Mercedes, 75 km N de Mercedes, Laguna Trin, Ea. Culantrillar, 24 October 1975, A. Schinini 11758 (MBM 048606). San Miguel, rutas 5 y 17, Ea. Curuzú Laruel, 09 November 1981, Vanni, R. 155 (EAC 0013648 [photo!]). ENTRE RÍOS: Concepción del Uruguay, 27 October 1980, Troncoso, N. S. & Bacigalupo, N. 2950 (CEN 00014377 [photo!]). Diamante, 20 km ruta a Paraná, 16 December 1960, Burkart, A. 22192 (F 0458842 [photo!]). Federación, ruta 114, desvio a Salto Grande, 14 December 1974, Burkart, A. et al. 30856 (SP 025944 [photo!]). Gualeguaya, barrancas del A. Clé, 22 October 1949, Burkart, A. 18106 (F 0458841 [photo!]). La Paz, 19 January 1960, Burkart, A. et al. 21207 (MBM 0147516). Victoria, Molino Doll, 26 January 1982, Troncoso, N. S. et al. 3279 (P 03570127 [photo!]). Villaguay, 27 October 1961, Pedersen, T. M. 6291 (US 02046802). RÍO NEGRO: en las lomadas del Rio Negro, Feb 1916, Scala, A. C. 78 (F 0458840). BRAZIL. RIO GRANDE DO SUL: s.d., Sellow s.n. (L 1929956 [photo!]); 1833, Gaudichaud, C. 1520 (P 01167832 [photo!]); estância do Sr. Rotta, 16 November 1945, Swallen, J. R. 7386 (U 1245761 [photo!]). Alegrete, arroio Lajeadinho, 21 December 1981, Sobral, M. & Stehmann, J. 900 (ICN 00019010 [photo!]). Bagé, a 24 km da cidade, estrada Bagé-Serrilhada, 08 December 1990, L. A. Z. Machado 710 (SMDB 3751); 20 November 1993, Matzenbacher, N. I. s.n. (ICN 00019019 [photo!]); estrada de terra entre Bagé e Serrilhada, 20 km após Bagé, 28 November 1992, Miotto, S. T. S. et al. 1385 (ICN 00019022 [photo!]); em direção à Aceguá, 6 km após Bagé, 30 November 1996, Miotto, S. T. S. 1512 (ICN 00019032 [photo!]); BR-153 a 20 km de Aceguá, 28 November 1998, Miotto, S. T. S. 1638 (ICN 00019031 [photo!]); em frente à Fazenda Santa Genoveva, na estrada de Bagé para Serrilhada, 06 December 1982, Valls, J. F. M. et al. 6977 (ICN 00019009 [photo!]; CEN 00008029 [photo!]); 5 km a norte do marco geográfico de Aceguá, ao longo da rodovia BR-153, 29 November 1985, Valls, J. F. M. et al. 9614 (ICN 00019018 [photo!]); 5 km após o trevo Bagé-Aceguá, em direção a Aceguá, 30 November 1996, Neubert, E. E. 141 (ICN 00019024 [photo!]); on road side, 18 November 1993 Matzenbacher, N. I. 40 (F 0458836 [photo!]). Dom Pedrito, 03 December 1982, Valls, J. F. M. et al. 6943 (UEC 55196; ICN 00019011 [photo!]; ICN 00019013 [photo!]); 10,3 km da fronteira com Uruguai, na Cruz de São Pedro em direção a Dom Pedrito, 07 December 1989, Valls, J. F. M. et al.12340 (ICN 00019021 [photo!]). Itaqui, posto Cambaí, junto a estrada de acesso a Itaqui, ao longo da rodovia BR-472, 16 March 1986, Valls, J. F. M. et al. 9790 (ICN 00019027 [photo!]). Quaraí, Chico-Cabanha Santo Ângelo, 14 November 1988, G. P. Beneton 215 (HAS 21835); 11 November 2009, Barbosa, E. 2559 (MBM 0355588; ALCB 028603 [photo!]). Santa Vitória do Palmar, Estação Ecológica do Taim, Fazenda Sta. Marta, margem noroeste da lagoa Mangueira, 03 November 1985, Jarenkow, J. A. 202 (FLOR 25954); 13 km de Santa Vitória do Palmar, 19 November 1986, Mattos, J. 29981 (HAS 84530); caminho para o porto, 26 November 2004, Boldrini, I. I. 1267 (ICN 00019030 [photo!]). Santana do Livramento, 29 November 1987, L. A. Z. Machado 13 (SMDB 3753); Área de Proteção do Ibirapuitã, 05 December 2020, Monteiro, T.C. & Monteiro, G.C 396 (BOTU 35340). Uruguaiana, Guará, nativo, 02 October 1988, Jardim, B. s.n. (MPUC 22278); margem do arroio Salso, ao S da cidade, ao longo da BR-472, 05 December 1985, Valls, J. F. M. 9688 (UEC 55202; ICN 00019023 [photo!]); November 1932, H. S. A. 18 (ICN 00019026 [photo!]); fazenda Itauassu, próximo ao arroio Pindaiassu, 19 March 1991, Valls, J. F. M. et al. 12800 (CEN 00090248). URUGUAY. 1838, Isabelle, A. s.n. (F 0458838 [photo!]). COLONIA: 80 a 100 m E de la intersección con Ruta 21, 31 November 2007, Seijo, J. G. 3986 (ASU 0066851 [photo!]). LAVALLEJA: Minas, próximo ao Cerro do Arequita, 06 January 2011, Iganci, J. R. V. et al. 762 (CTBS 160). MALDONADO: Piriápolis, em beira de estrada, 02 Feb 2008, Echeverrigaray, S. 03 (HUCS 34820). MONTEVIDEO: September 1828, Gay, C. s.n. (P 02936680 [photo!]); 24 November 1912, Osten, C. 6380 (US 02046817 [photo!]); Pocitos, December 1924, Herter, W. G. F. 459 (F 0458839 [photo!]; U 1245723 [photo!]). PAYSANDÚ: ruta 3 y Ayo, Chapicuy, 04 December 2001, Seijo, J. G. 2707 (HUEFS 071092 [photo!]). ROCHA: Ponte San Miguel, 09 November 2009, Barbosa, E. 2299 (MBM 355596).