<b>Ontogeny of the pericarp of <i>Serjania communis</i> Camb. and <i>Urvillea ulmacea</i> Kunth (Sapindaceae) with emphasis on the dispersion apparatus

Abstract

The pericarp development of Serjania communis Camb. and Urvillea ulmacea Kunth was described to expand the structural knowledge of Sapindaceae fruit. Ovaries and fruits were analyzed with usual techniques in plant anatomy. Ovary is structurally similar and the occurrence of glandular and non-glandular trichomes varies between species. In S. communis, the samaroid schizocarp has proximal wings and distal cavities; in U. ulmacea, the fruit presents septicidal and septifragal passive dehiscence and each seed chamber presents a dorsal wing. The unistratified exocarp has long pluricellular, uniseriate and sparse trichomes in U. ulmacea. The mesocarp is spongy, parenchymatous and in S. communis it presents three distinguished regions. Dorsal, lateral and ventral vascular bundles are more developed in S. communis and fiber caps on the phloem in the lateral bundles have an important role on the mericarp separation. The endocarp derives from the adaxial meristem and its oblique and tangentially elongated cells become lignified. The wings originate from a more active meristem – at the ovarian edges – and by intense divisions of ovarian mesophyll in this region. Fruit of U. ulmacea can represent a transition state between the samaroid schizocarp formed by Serjania and the septifragal capsule produced by Cardiospermum.