Recent advances in molecular phylogenetics and a series of important palaeobotanical discoveries have revolutionized our understanding of angiosperm diversification. Yet, the origin and early evolution of their most characteristic feature, the flower, remains poorly understood. In particular, the structure of the ancestral flower of all living angiosperms is still uncertain. Here we report model-based reconstructions for ancestral flowers at the deepest nodes in the phylogeny of angiosperms, using the largest data set of floral traits ever assembled. We reconstruct the ancestral angiosperm flower as bisexual and radially symmetric, with more than two whorls of three separate perianth organs each (undifferentiated tepals), more than two whorls of three separate stamens each, and more than five spirally arranged separate carpels. Although uncertainty remains for some of the characters, our reconstruction allows us to propose a new plausible scenario for the early diversification of flowers, leading to new testable hypotheses for future research on angiosperms.

The patterns of trichome evolution indicate that most morphotypes are probably homologous in Bignonieae and could be treated under the same name based on its morphological similarity and common evolutionary history, in spite of the plethora of names that have been previously designated in the literature. The trichome descriptions presented here will facilitate comparisons across taxa, allowing inferences on the relationsthips between trichome variants and future studies about their functional properties.

The degree and diversity of fusions of floral organs in Galipeinae is unique within the order Sapindales. A study of the amount of diversification of Galipeinae in South America and comparison with other clades of Rutaceae would be of interest.

-(Floral morphology and anatomy of fi ve species of Galipea Aubl. and its bearing on the evolution of tubular fl owers in Neotropical Rutaceae). Most genera of the neotropical subtribe Galipeinae (tribe Galipeeae, Rutoideae) have tubular fl owers with several forms and degrees of fusion between parts. The fact that Galipea and other genera in the subtribe bear only two fertile anthers plus fi ve or more staminodes is also intriguing, since generally the Galipeeae exhibit isostemony. To elucidate the anatomic condition of these traits, and to establish an accurate coding scheme for characters state in phylogenetic studies, a morphoanatomical study of the fl ower of fi ve species of Galipea was carried out. Using cross-sections of pickled material, the patterns of vascularization, position, and union of the fl ower segments were investigated. Noteworthy results are: 1) a true fl oral tube is formed in the basal third part of the fl ower through the connation of fi laments and the adnation of this staminal tube to the petals; 2) the petals are distally coherent to each other and adherent to the fi laments by means of capillinection (close intertwining of trichomes) -a case of pseudosympetaly; 3) from the usually fi ve linear structures referred to as staminodes, only the three external ones are homologous to fully sterilized stamens, while the other ones arise as branches from the petals; 4) carpels are congenitally connate axially and laterally, except for a small area close to the top of the ovary where they are postgenitally united; 5) the vascularization of the disc suggests a receptacular origin. The implications of these data for the evolution of tubular fl owers in Galipea and related groups are discussed.Key words -fl oral anatomy, pseudosympetaly, Sapindales, staminodes, tubular fl owers RESUMO -(Morfoanatomia da fl or de cinco espécies de Galipea Aubl. e seu signifi cado na evolução de fl ores tubulosas entre as Rutaceae neotropicais). A maioria dos gêneros da subtribo neotropical Galipeinae (tribo Galipeeae, Rutoideae) tem fl ores tubulosas, com várias formas e graus de conação e adnação. Galipea e outros gêneros na subtribo apresentam apenas duas anteras férteis mais cinco ou mais estaminódios, o que é intrigante porque na tribo predominam fl ores pentâmeras isostêmones. Visando elucidar a condição anatômica dessas características e estabelecer estados acurados para caracteres em análises fi logenéticas, um estudo morfoanatômico de fl ores de cinco espécies de Galipea foi realizado, buscando os padrões de vascularização, posição, e união dos segmentos da fl or. Destacam-se os resultados: 1) um tubo fl oral genuíno se forma no terço basal da fl or por conação dos fi letes e adnação desse tubo estaminal às pétalas; 2) as pétalas são distalmente coerentes umas às outras e aderentes aos fi letes por meio de entrelaçamento de tricomas densos -um caso de pseudossimpetalia; 3) dentre as cinco (às vezes seis) estruturas tratadas como estaminódios, apenas as três externas são de fato homólogas a estames...