Seed and embryo morphology of Poecilanthe (Fabaceae, Papilionoideae, Brongniartieae) JOSÉ EDUARDO MEIRELES* and ANA MARIA G. DE A. TOZZI Departamento de Botânica, IB, Universidade Estadual de Campinas, Caixa Postal 6109, CEP 13083-970, Campinas – SP, Brazil Received 15 May 2008; accepted for publication 16 May 2008 This work analyses and describes seed and embryo morphology of eight Poecilanthe species. Poecilanthe species can be divided in four groups based on seed and embryo characters: (1) P. amazonica-type has overgrown seeds, bears cataphylls on the epicotyl and has an inflexed hypocotyls-root axis; (2) P. effusa-type has two types of trichomes on the epicotyl, which is longer than the hypocotyls-root axis; (3) P. parvilora-type has a visible lens and the raphe runs around three-quarters of the seed circumference; and P. grandiflora-type bears a one-lipped rim aril. Poecilanthe presents a remarkable diversity both in seed and embryo, which reinforces the belief that the genus is not monophyletic. Moreover, our results support the three major clades recognized by a preliminary phylog- eny. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158, 249–256. ADDITIONAL KEYWORDS: aril – cataphylls – chalaza – hypocotyls-root axis – legume – Leguminosae – lens – neotropics – plumule – taxonomy – trichomes. INTRODUCTION The genus Poecilanthe (Fabaceae, Papilionoideae, Brongniartieae), established by Bentham (1860), com- prises ten South American species distributed from Colombia and French Guiana to East Argentina and Uruguay (Meireles & Tozzi, 2007). Poecilanthe species are shrubs or trees occurring in a wide range of habitats, such as flooded and non-flooded Amazonian forest, Atlantic rain forest, savannah (cerrado) and seasonally dry forests, including caatinga and restinga. The genus has a remarkable morphological diver- sity. Geesink (1981) pointed out that Poecilanthe could be divided in two groups, one with unifoliolate leaves and racemose inflorescences and the other with imparipinnate leaves and paniculate inflorescences. The androecium can be monadelphous or diadel- phous, with its anthers strongly dimorphic or just sub-equal and fruits can be internally septate or not (Meireles & Tozzi, 2007). According to Greinwald et al. (1995), one group of species accumulates a-pyridone alkaloids whereas the other group accu- mulates bicyclic quinolizidine alkaloids, with the a-pyridone type being absent. Kirkbride, Gunn & Weitzman (2003) analysed four species of Poecilanthe and remarked that this genus presents two distinct seed morphologies. One group has a hard and glossy testa, straight embryonic axis and the seed length at right angles to the fruit length [e.g. P. effusa (Huber) Ducke, P. itapuana G.P.Lewis and P. subcordata Benth.]. The other group has a thin and dull testa, curved embryonic axis and the seed and fruit length parallel, as in P. amazonica (Ducke) Ducke. Seed and embryo characters have been tradition- ally used in legume taxonomy. Many authors includ- ing Gunn (1981, 1984), Lima (1985), Lima (1989), Oliveira (1999) and Kirkbride et al. (2003), have shown the importance of such characters to legume taxonomy. This work aims to improve the knowledge of Poecilanthe seed and embryo morphology and to check for useful characters to the taxonomy of this polymorphic genus. *Corresponding author. E-mail: jemeireles@gmail.com Botanical Journal of the Linnean Society, 2008, 158, 249–256. With 2 figures © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158, 249–256 249 Downloaded from https://academic.oup.com/botlinnean/article/158/2/249/2418263 by guest on 10 November 2022