Most genera of the neotropical subtribe Galipeinae (tribe Galipeeae, Rutoideae) have tubular flowers 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 five 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 flower of five species of Galipea was carried out. Using cross-sections of pickled material, the patterns of vascularization, position, and union of the flower segments were investigated. Noteworthy results are: 1) a true floral tube is formed in the basal third part of the flower through the connation of filaments and the adnation of this staminal tube to the petals; 2) the petals are distally coherent to each other and adherent to the filaments by means of capillinection (close intertwining of trichomes) - a case of pseudosympetaly; 3) from the usually five 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 flowers in Galipea and related groups are discussed.
floral anatomy; pseudosympetaly; Sapindales; staminodes; tubular flowers
