title: Flower development of Goniorrhachis marginata reveals new insights into the evolution of the florally diverse detarioid legumes.
abstract: OBJECTIVE
  The study of floral morphology and ontogeny and the re-investigation of existing data help to uncover potential synapomorphic characters and foster our understanding of phylogenetic relationships that rely primarily on molecular analyses. Goniorrhachis marginata is a monotypic caesalpinioid legume (Leguminosae) that shows some interesting floral features, such as a long hypanthium and regular Rosaceae-like flowers. We studied the ontogeny and morphology of the flowers in detail and present our results in a broad phylogenetic context.
  
  
  METHODS
  Flower buds were collected in the field, fixed in 70 % ethanol and investigated using scanning electron microscopy. Older buds in spirit were carefully opened to investigate the direction of style bending. Characters of the style from 131 taxa from the main legume lineages were analysed and mapped on a Bayesian molecular phylogeny.
  
  
  RESULTS
  The tetramerous calyx is the result of complete loss of one sepal. The formation of the radially symmetrical corolla starts in a typical caesalpinioid pattern with the adaxial petal innermost (ascending aestivation). The young style bends in the abaxial direction, which is a character found exclusively in all studied detarioid legumes and therefore a newly described synapomorphy for the clade.
  
  
  CONCLUSIONS
  We show that investigation of unstudied taxa and reinvestigation of published data can uncover new, previously overlooked and important characters. Curvature of the style can be detected in young buds with a hand lens and therefore is an important character for field botanists. Our study reveals the importance of including poorly studied and/or phylogenetically enigmatic taxa in molecular phylogenies and in detailed morphological and ontogenetic analyses.
authors.affiliation: Royal Botanic Gardens, Kew, Jodrell Laboratory, Richmond, Surrey TW9 3DS, UK g.prenner@kew.org.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Prenner
authors.affiliation: National Institute of Science and Technology in Interdisciplinary and Transdisciplinary Studies in Ecology and Evolution (INCT IN-TREE), Instituto de Biologia, Universidade Federal da Bahia, Rua Barão de Jeremoabo, s/n, Ondina, 40170-115, Salvador, Bahia, Brazil.
authors.forename: Domingos
authors.initials: D
authors.lastname: Cardoso
mesh_terms: D001499:Bayes Theorem; D005075:Biological Evolution; D019143:Evolution, Molecular; D007887:Fabaceae / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development* / Q000648:ultrastructure; D035264:Flowers / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development* / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D010802:Phylogeny
keywords: Caesalpinioideae; Detarieae; Leguminosae; flower development; flower evolution; flower symmetry; gynoecium; style