• Chamaecrista desvauxii var. latistipula;
  • Chamaecrista flexuosa;
  • Chamaecrista nictitans var. patellaria;
  • Fabaceae;
  • morphology;
  • seed anatomy;
  • seed coat;
  • SEM;
  • surface micromorphology;
  • testa

According to the literature, the seeds of Chamaecrista lack pleurograms and have pitted testas aligned in vertical lines. Preliminary observations have revealed that these small structures consist of superficial alterations of the testa that are coloured differently to the rest of the seed coat and stand out as pits. However, no anatomical inspection has yet determined the precise composition of these pits. The present work examined the morphology, surface micromorphology, anatomy, and histochemistry of the seed coat of mature seeds of C. desvauxii var. latistipula, C. flexuosa, and C. nictitans var. patellaria in order to elucidate the structural nature of the seed coat pits. For this, seed coats were studied using scanning electron microscopy and light microscopy. Structural modifications were examined in the seed coats of the studied species, and variations were noted in the mucilaginous layer, in the thickness of the palisade layer, and in the presence of larger hypodermic cells. Based on the anatomical features observed, and comparing these with published data on pleurograms in the Caesalpinioideae, it was determined that the structures referred to previously as tegumental pits on Chamaecrista seeds are actually small and numerous pleurograms, reported here for the first time. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 157, 487–492.