In the present study, we assessed the seed germination responses of Cereus jamacaru DC. ssp. jamacaru (Cactaceae) to environmental factors. The seeds were collected from an area within Caatinga, a semiarid vegetation area located in north-eastern Brazil. We determined the optimal temperature for germination of C. jamacaru seeds and evaluated the effect of temperature, light intensity, light quality, water and saline stress on seed germination. Cereus jamacaru was classified as a positive photoblastic species. Maximum germination (95.8 Ϯ 2.6%) was found under white light, and seed germination was not observed in darkness in any of the temperature, water or saline stress treatments. The optimum temperature for seed germination was 30°C because this temperature favored most of the parameters evaluated. Seed germinability responded positively to a wide range of temperatures, but was affected neither by light intensity nor by light quality. A reduction in water availability and an increase in saline concentration affected germinability and promoted slower, unsynchronized germination. The positive response of C. jamacaru seed germination to the environmental factors investigated may account for the abundant occurrence and wide distribution of the species in the Caatinga area.

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Neste trabalho realizou-se o tratamento sistemático das Cactaceae do Pico do Jabre, Paraíba, Brasil. A área de estudo é o ponto mais alto do Nordeste setentrional, constitui-se de um enclave de mata serrana, sendo considerada um dos poucos representantes da Paraíba incluídos no domínio da Mata Atlântica. No Pico do Jabre, as Cactaceae estão representadas por três gêneros e quatro espécies: Cereus jamacaru DC., Melocactus ernestii Vaupel, Pilosocereus chrysostele (Vaupel)Byles & Rowley e Pilosocereus gounellei (F.A.C.Weber)Byles & Rowley.

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RESUMO -(Flora da Paraíba, Brasil: Combretaceae). Apresenta-se o tratamento taxonômico da família Combretaceae como parte do projeto "Flora da Paraíba", que vem sendo realizado com o objetivo de identificar e catalogar as espécies da flora local. As identificações, descrições e ilustrações botânicas foram efetuadas pela análise morfológica de amostras frescas e espécimes herborizados, com o auxílio da bibliografia e análise de tipos, complementadas pelas observações de campo. Foram registradas 11 espécies subordinadas a cinco gêneros: Buchenavia (1), Combretum (8), Conocarpus (1) e Laguncularia (1). Algumas espécies possuem distribuição restrita aos manguezais, como Conocarpus erectus L. e Laguncularia racemosa (L.) C.F. Gaertn., à Caatinga, como Combretum glaucocarpum Mart., C. leprosum Mart. e C. hilarianum D. Dietr., e a Floresta Atlântica, como Buchenavia tetraphylla (Aubl.) R.A. Howard, Combretum fruticosum (Loefl.) Stuntz e C. laxum Jacq. Palavras-chave:Combreteae, Combretoideae, flora paraibana, Laguncularieae, Myrtales, Nordeste brasileiro ABSTRACT -(Flora of Paraíba, Brazil: Solanum L., Solanaceae). This taxonomic treatment of the genus Solanum is part of the "Flora da Paraíba" project which aims to identify and catalogue the species of the local flora. Botanical collections, field observations and morphological studies were done for identification, description and botanical illustration of the plant species, also supported by the literature and analysis of Brazilian and foreign herbaria, plus specimens from EAN and JPB herbaria. Twenty two species of Solanum were recorded in the state of Paraíba: Solanum agrarium Sendtn