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 11. Sida paradoxa Rodrigo (1937: 105) ( Figures 5 , 6E–J , 14K ). Lectotype (designated here):— ARGENTINA . Corrientes . Mercedes , “Arroyo Las Garzas”, November 1936 , A . P . Rodrigo 605 ( LP barcode 004331! [digital image]; isolectotypes LP barcode 004334! [digital image], LP barcode 004335! [digital image]; NY 00222038 ! [digital image], K 000528458 [digital image]). Nomenclatural notes: — Sida paradoxa was described by Rodrigo (1937) who designated the collection “Rodrigo 605” deposited in LP as type. However, there are three specimens under this collection number in the LP herbarium. Therefore, a lectotypification was necessary. An image of one of the specimens deposited in the LP herbarium was used by Rodrigo (1937) as a figure in the original description of the species. This specimen was chosen to be the lectotype . FIGURE 5. Distribution map of Sida glaziovii , S. paradoxa , S. linifolia , S. nemorensis , S. planicaulis , S. potentilloides and S. rubifolia in Rio Grande do Sul state, Brazil. FIGURE 6. A–D. Sida nemorensis . A. Flower. B. Branch with leaves and flowers. C. Leaves and schizocarps. D. Calyx and mericarps. E–J. Sida paradoxa . E. Flower. F. Branch with leaves and stipules. G. Abaxial surface of leaf. H. Habit. I–J. Schizocarps. K–P. Sida planicaulis . K. Flowers. L. Adaxial surface of leaf. M. Abaxial surface of leaf. N. Branch with distichous leaves arrangement. O. Schizocarps. P. Branch with flowers and schizocarps. Photographs A–B by Amaury Junior, C–P by Martin Grings (C–D from Krapovickas & Cristóbal 38480, HAS). Taxonomic notes: —The species is distinguished from other species of section Malacroideae by its stems without roots; subentire margin of leaves, only with three apical teeth; staminal tube glabrous; petals 17 mm long ( Figures 6E– J , 14K ; Table 1 ) ( Krapovickas 2006 ). Sida paradoxa can be distinguished from the other species of Sect. Malacroideae of Rio Grande do Sul , Sida anomala , by the cuneate-truncate leaf blades, subentire, with three teeth at the apex; flowers 2.5 cm in diameter; fruits with 5 mericarps (vs. linear leaf blades, serrate in the upper half; flowers 2 cm in diameter; fruits with 7–8 mericarps). In the present work, photos of the species in its habitat are presented for the first time. Distribution, habitat and conservation status: — Sida paradoxa occurs in Argentina (only in Corrientes province ) and in Brazil , only in state of Rio Grande do Sul ( Krapovickas 2005 , Zuloaga et al. 2008 , Bovini 2020 ), in Park grassland ( Figure 5 ). With the available records, the species presents an EOO of 46,921.776 Km² and an AOO of 100 Km². The species is here considered Endangered (EN), criterion B2b(i, ii, iii)c(i, ii), due to the continuous reduction observed in its habitat and its area of occupancy ( Mapbiomas 2020 ). Representative specimens: — BRAZIL . Rio Grande do Sul . Barra do Quaraí , Parque Estadual do Espinilho , 50 m , 30º11’22.5”S 57º29’46.5”W , 12 December 2009 , M . Grings & R . Paniz 889 ( ICN ) .