Synopsis of Sida (Malvoideae, Malvaceae) in the state of Rio Grande do Sul, Brazil Author Grings, Martin Programa de Pós-Graduação em Botânica, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500, Porto Alegre, Rio Grande do Sul, 91501 - 970, Brazil. Author Boldrini, Ilsi Iob Programa de Pós-Graduação em Botânica, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500, Porto Alegre, Rio Grande do Sul, 91501 - 970, Brazil. text Phytotaxa 2022 2022-04-05 542 2 105 135 http://dx.doi.org/10.11646/phytotaxa.542.2.1 journal article 53645 10.11646/phytotaxa.542.2.1 8b5747ec-68d6-4c6a-a1a0-c0c1152b45cc 1179-3163 6415487 5. Sida dubia A. Saint-Hilaire & Naudin (1842: 50) ( Figures 2 , 3F–J , 14G ). Holotype :— BRAZIL . s.l., s.d., C . Gaudichaud 1220 ( P barcode 02285395! [digital image]). = Sida multicrena Hochreutiner (1905: 295) Holotype :— PARAGUAY . In campo Apepu (Tapiraguay) , Aug., Hassler 4351 (G barcode 00306074! [digital image]). Taxonomic and nomenclatural notes: —The species S. multicrena , was synonymized by Krapovickas (2005) , which we agree after analyzing the types of both. Sida dubia belongs to section Cordifoliae by the indument densely stellate-tomentose; leaf blades lanceolate, dentate-crenate throughout, basally more or less cordate, features pointed out by Fryxell (1985) for this section ( Table 1 ). The species can be recognized by its erect habit, pink corolla (rarely yellow), 11–13 mericarps with aristae 1–3 mm long ( Figures 3F–J , 14G ). Distribution, habitat and conservation satus: — Sida dubia occurs in northeastern Argentina , Paraguay , Uruguay , and Brazil ( Krapovickas 2005 , Zuloaga et al. 2008 , Bovini 2020 ). Specifically in Brazil , the species occurs only in State of Rio Grande do Sul , in Shallow soil grassland, Bush grassland, Inland sub-montane grassland, Sandy grassland, Coastal grassland, and Aristida grassland ( Figure 2 ). With the available records, the species presents an EOO of 298,741.879 Km² and an AOO of 400 Km². Although it can be considered EN by the AOO, conditions B(a), B(b) and B(c) were not met. Therefore, the species is here considered Least Concern (LC). However the situation of the species must be monitored, since it is restricted to Pampa grasslands which has suffered great losses in area (30% from 1985 to 2019) due to conversion to crops in the state of Rio Grande do Sul , Brazil ( Andrade et al. 2015 , Mapbiomas 2020 ). Representative specimens: — BRAZIL . Rio Grande do Sul . Alegrete , Reserva Biológica do Ibirapuitã S 29º54’59.5” W 55º46’00.0”, 14 December 2009 , M . Grings & R . Paniz 1916 ( ICN ); Cerro Largo, São Luiz, January 1943 , P . Buck s.n. ( PACA 11127 ); Mostardas, Lagoa do Peixe , 21 February 1970 , E . Vianna et al. s.n. ( ICN 7529 ); Porto Alegre, Morro Teresópolis, 27 May 1980 , S . Martins 315 ( ICN ); Santana da Boa Vista , BR 392 , WGS 84 S 30º47’54.3” W 053º11’24.9”, 23 November 2018 , M . Grings & J . Schaefer 1975 ( ICN ); São Francisco de Assis , Gruta São Tomé , 20 April 2008 , E . Mundeleski 58 ( ICN ) .