Dimorphic cypsela germination and plant growth in Synedrella nodiflora (L.) Gaertn. (Asteraceae)

synedrella nodiflora is a weed species that has dimorphic cypselas: winged peripheral and lanceolate shaped central. the aim of this work is to describe the reproductive capability by measuring dimorphic cypselas morphology, imbibition rates and germinative patterns under temperature, light quality and water availability gradients, and compare the plant growth between two light treatments. the central cypselas were lighter, longer and its pappi were more elongated than the peripheral ones, favoring its dispersion. neither type had deep dormancy and both of them germinated with the same pattern under the optimum conditions. both cypselas showed higher germinability in temperatures between 25 and 30 °c, under white light and high water availability, although there are some differences between the types, mainly at dark treatments. plants grown in direct sunlight accumulated more biomass, allowing for higher plant development and inflorescence production, although shaded light plants capitulum had a higher central: peripheral ratio than the direct sunlight treatment. s. nodiflora cypselas germinate better in unfiltered light places, although the plants are adapted to shady conditions. the species showed high germination potential over a wide range of environmental conditions, as well as fast plant development. all of these features favor distribution in environmental sites.