Croton uruguayensis Baillon (1864: 292)

Pereira, Amanda Da Paixão Noronha, Riina, Ricarda & Caruzo, Maria Beatriz Rossi, 2022, Croton (Euphorbiaceae) of the Brazilian state of Paraná: an annotated checklist, species distribution, and identification key, Phytotaxa 570 (3), pp. 231-274 : 264

40. Croton uruguayensis Baillon (1864: 292) .

Lectotype (designated by Lima & Pirani 2008b, second step designated here): — URUGUAY. ‘ Banda oriental del Uruguay’, 1816-1821, A. Saint-Hilaire C2-2449 ( P 00634813 !; isolectotypes P 00634814!, A 00047459!). (Illustration available in Lima & Pirani 2008b: 221)

Croton uruguayensis is a shrub that can be distinguished from other Croton in Paraná by its narrow leaves with glabrous adaxial surface and lepidote abaxial surface, inflorescences unisexual and elongated. The species is similar to C. longicarpus (see under C. longicarpus ). The species can be also confused with C. myrianthus by its unisexual inflorescence (see under C. myrianthus ). Smith et al. (1988), described the inflorescences of the species as bisexual, but all the collections examined have only unisexual thyrses, as noted by Lima & Pirani (2008b). Some collections were identified as C. gaudichaudii Baillon (1864: 293) , however, that name was synonymized under C. uruguayensis ( Lima & Pirani 2008b), and we agree with that because they exhibit overlapping characters. The species is a member of section Lamprocroton subsect. Lamprocroton .

Distribution and habitat:— It occurs in Argentina, Paraguay, Uruguay, and Brazil (PR, RS, SC), and Bolivia ( Lima & Pirani 2008 b, Caruzo et al. 2020). In Paraná, it is found near riverbanks, principally along the Rio Iguaçu, and, rarely in open vegetation ( Smith et al. 1988), between 215 and 990 m elevation ( Fig. 20 ).

Phenology:— Flowering and fruiting from June, July, and October to January.

Representative specimens:— PARANÁ: Capanema, Parque Nacional do Iguaçu , Rio Iguaçu, 30 October 2015, M. G . Caxambu, E. L . Siqueira & J . Pommer 7107 ( HCF). Capitão Leônidas Marques , próximo ao Parque Nacional do Iguaçu, 01 June 2004, P . Labiak, O. S . Ribas & M. P . Petean 3366 ( MBM, UPCB). Dois Vizinhos , Foz do Rio Chopim, 09 December 1968, G . Hatschbach & O . Guimarães 20578 ( MBM, NY, UPCB). São Mateus do Sul , Fazenda do Durgo, inundação do Rio Iguaçu, 21 July 1986, R. M . Britez 826 ( MBM). Idem , Várzea da Olaria, 17 January 2006, J. M . Silva & O. S . Ribas 4584 ( MBM). União da Vitória , São Cristóvão, 18 November 1972, G . Hatschbach 30678 ( MBM, NY, W) .

Figures

FIGURE 20. Map showing the known geographic distributions of Croton trinitatis, C. triqueter, C. urucurana, C. uruguayensis, and C. vulnerarius in Paraná state.