To better understand the role of seed banks in ecological succession of dry forests, we compared similarities between vegetation and seed banks and assessed the relative contributions of seed dispersal and persistence in chronosequences in the Brazilian semi-arid region. To sample the standing vegetation and the seed bank, we collected data in three sites with three successional ages in each one (5 y, 25 y and 45 y). A total of 180 soil samples (three sites × three successional ages × 10 plots × two components) were collected. The composition of the seed bank was assessed by the seedling emergence method. Of 166 species identified in the standing vegetation, only 50 (30.1%) were also present in the seed bank, resulting in low similarity (Jaccard index = 0.02–0.21) and reflecting the rarity of woody species and the dominance of annuals (71% of richness). The relative importance of seed persistence and seed dispersal to seed banks composition were balanced in most cases (difference was not rejected in four out six comparisons). Those results suggest that seed banks in tropical dry forests are largely the result of high dispersal rates and the persistence of allochthonous annual species that contribute to decoupling seed bank and vegetation composition.

Resumo Apresentamos um levantamento florístico de Cleomaceae no estado do Ceará, como parte do projeto "Flora do Ceará". O estudo baseou-se na análise dos caracteres morfológicos de espécimes depositados nos herbários EAC, HCDAL, HST, HUEFS, JPB, MOSS, R e UFRN, bibliografias especializadas, fotos de materiais-tipo, além de coletas e observações de campo. Foram registradas dez espécies pertencentes a cinco gêneros: Cleome (C. microcarpa), Gynandropsis (G. gynandra), Hemiscola (H. aculeata e H. diffusa), Physostemon (P. guianense, P. lanceolatum subsp. lanceolatum, P. rotundifolium e P. tenuifolium) e Tarenaya (T. spinosa e Tarenaya curvispina). Dentre estas, Tarenaya curvispina é uma nova espécie, e Gynandropsis gynandra e Physostemon tenuifolium representam duas novas ocorrências para o estado. Em território cearense, as espécies estão associadas a ambientes úmidos (floresta ombrófila densa) e secos (floresta estacional semidecidual de terras baixas, savana estépica e floresta estacional decidual).