RESUMO Cuscuta é amplamente distribuído e possui aproximadamente 200 espécies de parasitas volúveis. Estima-se que ocorram 26 espécies no Brasil, porém, não há estudos atuais publicados para a flora do país. Por meio de extensa revisão bibliográfica, de materiais de herbários e expedições a campo, foram reconhecidos 15 táxons de Cuscuta na Região Sul do Brasil (Estados do Paraná, Santa Catarina e Rio Grande do Sul): Cuscuta boliviana, C. campestris, C. corniculata, C. epilinum, C. incurvata, C. indecora var. neuropetala, C. obtusiflora, C. odorata, C. orbiculata, C. platyloba, C. racemosa, C. taimensis, C. xanthochortos var. xanthochortos, C. xanthochortos var. carinata e C. xanthochortos var. lanceolata. Uma nova espécie foi descrita (C. taimensis P.P.A. Ferreira & Dettke) e novas ocorrências para os Estados e uma para o Brasil foram confirmadas durante este estudo. São fornecidas chave de identificação, descrições morfológicas, ilustrações, além de dados de distribuição geográfica e habitat dos táxons.

ABSTRACT Cuscuta is widely distributed and comprises about 200 species of parasitic vines. It is estimated that 26 species of Cuscuta occur in Brazil, however, there are no recent published studies concerning the flora of this country. We found fifteen taxa of Cuscuta regarding of the Southern Brazil (Paraná, Santa Catarina e Rio Grande do Sul states): Cuscuta boliviana, C. campestris, C. corniculata, C. epilinum, C. incurvata, C. indecora var. neuropetala, C. obtusiflora, C. odorata, C. orbiculata, C. platyloba, C. racemosa, C. taimensis, C. xanthochortos var. xanthochortos, C. xanthochortos var. carinata and C. xanthochortos var. lanceolata. One new species was described (C. taimensis P.P.A. Ferreira & Dettke) and new records were confirmed for states and Brazil. We provide a key to species of Cuscuta, morphological descriptions, illustrations, information about geographic distribution and habitat.

ABSTRACT Most studies concerning climbing plants have focused on lianas, forest ecosystems, and tropical regions. Thus, the majority of existing information is not relevant to all climbing plants (lianas and vines) or all ecoregions of the world (forested and non-forested). We provide an update on floristic and distributional data available for climbing plants in Rio Grande do Sul, Brazil’s southernmost state, which is located within subtropical and temperate zones and includes a variety of forest and non-forest vegetation types. A total of 448 climbing plant species were confirmed and documented by voucher specimens, revealing a diversity similar to that registered for trees in the state (533). The significant contribution of climbing species to the regional flora, the differences in floristic composition and species richness among the state’s eight vegetation types, and the high number of endangered species found in this extratropical region reveal the requirement to expand studies of climbing plants to include environments beyond tropical forests. Furthermore, the importance of herbaceous climbing species in subtropical and temperate floras demonstrates that they should be included in ecological studies of climbing plants, and that future analyses could detect unique or divergent patterns between herbaceous and woody climbers.

Merremia Dennst. ex Endl. compreende aproximadamente 60 espécies, amplamente distribuídas nos trópicos e subtrópicos de ambos os hemisférios. Das 14 espécies do gênero conhecidas para o Brasil, nove foram confirmadas para a Região Sul: M. cissoides (Lam.) Hallier f., M. digitata (Spreng.) Hallier f. var. digitata, M. digitata var. elongata (Choisy) D.F.Austin & Staples, M. dissecta (Jacq.) Hallier f., M. hassleriana (Chodat) Hassl., M. macrocalyx (Ruiz & Pav.) O'Donell, M. tomentosa (Choisy) Hallier f., M. tuberosa (L.) Rendle e M. umbellata (L.) Hallier f. São fornecidos chave de identificação, descrições morfológicas, dados de distribuição geográfica, hábitat e ilustrações dos táxons. Merremia hassleriana constitui uma nova ocorrência para o Paraná.

Merremia Dennst. ex Endl. comprises about 60 species widely distributed in the tropics and subtropics of both hemispheres. Among the 14 species occurring in Brazil, nine were confirmed for the Southern region: M. cissoides (Lam.) Hallier f., M. digitata (Spreng.) Hallier f. var. digitata, M. digitata var. elongata (Choisy) D.F.Austin & Staples, M. dissecta (Jacq.) Hallier f., M. hassleriana (Chodat) Hassl., M. macrocalyx (Ruiz & Pav.) O'Donell, M. tomentosa (Choisy) Hallier f., M. tuberosa (L.) Rendle, and M. umbellata (L.) Hallier f. Analytical key, morphologic descriptions, geographical data, habitat and illustrations of the taxa of Merremia in Southern Brazil are provided. Merremia hassleriana is a new record for Paraná State.