Sida rubifolia A. Saint-Hilaire (1825: 183–184)

Grings, Martin & Boldrini, Ilsi Iob, 2022, Synopsis of Sida (Malvoideae, Malvaceae) in the state of Rio Grande do Sul, Brazil, Phytotaxa 542 (2), pp. 105-135 : 126

19. Sida rubifolia A. Saint-Hilaire (1825: 183–184) ( Figures 5 , 11A–D , 14R ).

Lectotype (designated here):— BRAZIL. Rio Grande do Sul. 1820–1821, A. St.-Hilaire C2 /2759 bis ( P barcode 02285470! [digital image]; isolectotypes P barcode 02285472! [digital image], P barcode 02285471! [digital image], MPU barcode 016967! [digital image]).

= Sida pseudorubifolia Krapovickas & Bueno (2007a: 203) . Syn. nov. Holotype:— BRAZIL. Rio Grande do Sul. Tupanciretan, in campo, 29 January 1942, Rambo 9472 (PACA!; isotype LIL).

Taxonomic notes: —According to Krapovickas (2007a) the species belongs to the section Cordifoliae due to the presence of subcordate leaves and 10 mericarps ( Table 1 ). Sida rubifolia can be distinguished from other species in the section by the prostate or decumbent habit; mericarps 4 × 2.5 mm; petals 20 mm long, yellow or pink. In the present work, photos of the species in its habitat are presented for the first time ( Figures 11A–D , 14R ).

Nomenclatural notes: —The specimen P 02285470, chosen as a lectotype, has two labels, the one on the right referring that the collection was carried out in Rio Grande do Sul state under number C2/2759 bis and the left label with informations that the collection was carried out in Minas Gerais state, as stated in the protologue. In Herter (1945) we can see that the collection C2/2759 bis of A. Saint-Hilaire was carried out in the state of Rio Grande do Sul, in a region that includes the locations of Quaraim (Quaraí), Ibicui, Santa Borja (São Borja), São Luis (São Luiz Gonzaga), São Miguel (São Miguel das Missões), São João, Rio Pardo, where the species actually occurs. In Dwyer (1955) we can also see that collections 2567–2797 of A. Saint-Hilaire were carried out in State of Rio Grande do Sul. In other words, A. St.-Hilaire was in Rio Grande do Sul on the date of collection of Sida rubifolia . Examining the type materials, we found that they are in accordance with the morphology of the species found in Rio Grande do Sul. The morphology of S. rubifolia , including mericarps, in the illustration presented by A. Saint-Hilaire (1825) is also in accordance with the morphology of the plant that occurs in the state of Rio Grande do Sul. In addition, the species was never found again in Minas Gerais, as mentioned in the protologue. There seems to be an error in the location shown in the protologue. Krapovickas and Bueno (2007a), in the description of Sida pseudorubifolia , do not morphologically distinguish it from Sida rubifolia . After analyzing the type and protologue of both, it was concluded that Sida pseudorubifolia Krapovickas & Bueno is the same species already described as Sida rubifolia A.St. -Hilaire. Therefore, we propose the synonymization of Sida pseudorubifolia .

Distribution, habitat and conservation status: —This species is endemic to Rio Grande do Sul, where it occurs in distinct types of grasslands: Aristida grassland, Sandy grassland, Bush grassland and Inland sub-montane grassland ( Figure 5 ). According to IUCN (2017), criterion B2ab(iii), the species is considered Vulnerable (VU), with an Extent of occurrence of 32,319 km ², an Area of occupancy of 44 km ², and occurring in about 11 locations. In addition, state of Rio Grande do Sul is facing an increase in loss of grasslands, converted or degraded, mostly by soybean cropland ( Andrade et al. 2015).

Representative specimens: — BRAZIL. Rio Grande do Sul. Cachoeira do Sul, BR-290 próximo ao km 177, March 1985, O . Bueno 4368 (HAS); Encruzilhada do Sul, Serra dos Pedrosos, - 30.7697223º S - 52.9111111º W, 1º December 2012, M . Verdi & J.A. Jarenkow 6335 (FURB); Santiago, S 29º06’18” W 54º58’35”, 28 November 2019, S . Bordignon & J.R. Stehamnn, 5919 (UNILASALLE); São Francisco de Assis , RST 377 km 320, WGS 84 - 29.616944º S - 55.051111º W, 21 November 2008, E . Freitas 619 (ICN).

Figures

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 11. A–D. Sida rubifolia. A. Flower. B. Adaxial surface of leaf. C. Prostrate habit. D. Calyx and corolla. E–K. Sida spinosa. E. Flower. F. Abaxial surface of leaf. G. Adaxial surface of leaf. H. Habit. I. Mature schizocarp. J. Branch with tubercle at petiole base. K. Branch. L–Q. Sida tuberculata. L. Branch with leaves, mature and immature schizocarps. M. Adaxial surface of leaf. N. Abaxial surface of leaf. O. Mature schizocarps. P. Branch with flower. Q. Habit. Photographs by Martin Grings.

FIGURE 14. Mericarps. A. Sida anomala. B. Sida confusa. C. Sida farroupilhensis. D. Sida glaziovii. E. Sida cerradoensis. F. Sida cordifolia. G. Sida dubia. H. Sida linifolia. I. Sida lonchitis. J. Sida nemorensis. K. Sida paradoxa. L. Sida planicaulis. M. Sida potentilloides.N. Sida reitzii. O. Sida regnellii. P. Sida rhombifolia.Q. Sida riedelii. R. Sida rubifolia.S. Sida spinosa.T. Sida tuberculata. U. Sida urens. V. Sida viarum. Photographs by Martin Grings.