12. Sida planicaulis Cavanilles (1785: 24) (Figures 5, 6K–P, 14L).

Lectotype (first step designated by Krapovickas 2003: 104, second-step lectotypification designated here):— BRAZIL. Rio de Janeiro, June–July 1767, Commerson (P barcode 02273667! [digital image]; isolectotypes P barcode 02273666! [digital image], P barcode 02273665! [digital image], P barcode 00671945! [digital image]).

= Sida carpinifolia Linnaeus, f. Suppl. 307. 1781. “ in Madera in Horto Monasteri Sti. Francisci, F. Masson”. NON Miller 1768.

Nomenclatural notes: — Krapovickas (2003) chose the collection of Commerson in Rio de Janeiro, deposited in the herbarium P, as lectotype. However, there are four specimens of this collection in P herbarium. Therefore, according to Art. 9.17, of the International Code of Nomenclature for algae, fungi, and plants (Turland et al. 2018) a second step of lectotypification was necessary. The specimen P barcode 02273667 was chosen as lectotype because it is more representative, with the presence of fruits.

Taxonomic notes: — Krapovickas (2003) creates the section Distichifoliae and presents a taxonomic study of this section. Before this study, many authors treated the species in this section as belonging to a few polymorphic species, as in the case of Sida acuta Burman f. (1768: 147)(Fryxell 1988, Fuertes Aguilar 1995). Therefore, Sida planicaulis can often be found identified as S. acuta in herbaria. Sida planicaulis is distinguished from other species of section Distichifoliae by the presence of 7–8 mericarps, aristae 2 mm long, flowers in axilar glomerules, yellowish corolla, staminal tube glabrous (Figures 6K–P, 14L; Table 1) (Krapovickas 2003).

Distribution, habitat and conservation status: —This species occurs in Argentina (Misiones), and Brazil, in northeast, southeast, midwest and south (Zuloaga et al. 2008, Bovini 2020). The species expanded to Indian and Pacific Oceans regions (Krapovickas 2003). In state of Rio Grande do Sul the species occurs in Inland subtropical forest, Coastal subtropical Forest and Tropical Forest (Figure 5), in edges of Forests and in ruderal shaded environments, from 0 to 400 m of elevation. Sida planicaulis is here considered Least Concern (LC) because it has large EOO and AOO, since it is a frequent and often ruderal species and is present in more than one continent.

Representative specimens: — BRAZIL. Rio Grande do Sul. Machadinho, Linha Copueiro, February 2001, E . Peloso s.n. (HAS); Porto Alegre, Morro da Tapera, 04 December 2008, M . Grings 808 (ICN); Nova Petrópolis, São Jacó, entre a primeira e a segunda barragem, 340 m, WGS 84 29°23’14.75”S 51° 5’49.11”O, 17 May 2020, M . Grings, 2139 (ICN) ; São Lourenço do Sul, 1º Distrito, Passo do Coqueiro, 1º January 2003, G . Heiden 259 (ECT); Torres, Colônia São Pedro, 10 February 1984, K . Hagelund 14953 (ICN); Venâncio Aires, Porto Mariante, 21 May 1955, Pivetta 882 (PACA) .